business-central fails to clone repositories for proxy authentication in BRMS/BPMS

Issue

• When I use "Clone repository" to clone "https://github.com/jbossdemocentral/bpms-travel-agency-demo-repo.git", I get the following Exception.

09:51:21,331 ERROR [org.guvnor.structure.backend.repositories.RepositoryServiceImpl] (http-0.0.0.0:8080-6) Error during create repository: java.lang.RuntimeException: java.lang.RuntimeException: https://github.com/jbossdemocentral/bpms-travel-agency-demo-repo.git: cannot open git-upload-pack
        at org.guvnor.structure.backend.repositories.RepositoryServiceImpl.createRepository(RepositoryServiceImpl.java:283) [guvnor-structure-backend-6.4.0.Final-redhat-6.jar:6.4.0.Final-redhat-6]
        at org.guvnor.structure.backend.repositories.RepositoryServiceImpl.createRepository(RepositoryServiceImpl.java:197) [guvnor-structure-backend-6.4.0.Final-redhat-6.jar:6.4.0.Final-redhat-6]
        at org.guvnor.structure.backend.repositories.RepositoryServiceImpl$Proxy$_$$_WeldClientProxy.createRepository(RepositoryServiceImpl$Proxy$_$$_WeldClientProxy.java) [guvnor-structure-backend-6.4.0.Final-redhat-6.jar:6.4.0.Final-redhat-6]
...
Caused by: java.net.UnknownHostException: github.com
        at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:178) [rt.jar:1.7.0_79]
        at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172) [rt.jar:1.7.0_79]
        at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392) [rt.jar:1.7.0_79]
        at java.net.Socket.connect(Socket.java:579) [rt.jar:1.7.0_79]
        at sun.security.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:625) [jsse.jar:1.7.0_79]
        at sun.net.NetworkClient.doConnect(NetworkClient.java:175) [rt.jar:1.7.0_79]
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:432) [rt.jar:1.7.0_79]
        at sun.net.www.http.HttpClient.openServer(HttpClient.java:527) [rt.jar:1.7.0_79]
        at sun.net.www.protocol.https.HttpsClient.<init>(HttpsClient.java:275) [rt.jar:1.7.0_79]
        at sun.net.www.protocol.https.HttpsClient.New(HttpsClient.java:371) [rt.jar:1.7.0_79]
        at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.getNewHttpClient(AbstractDelegateHttpsURLConnection.java:191) [rt.jar:1.7.0_79]
        at sun.net.www.protocol.http.HttpURLConnection.plainConnect(HttpURLConnection.java:976) [rt.jar:1.7.0_79]
        at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:177) [rt.jar:1.7.0_79]
        at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1301) [rt.jar:1.7.0_79]
        at java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:468) [rt.jar:1.7.0_79]
        at sun.net.www.protocol.https.HttpsURLConnectionImpl.getResponseCode(HttpsURLConnectionImpl.java:338) [rt.jar:1.7.0_79]
        at org.eclipse.jgit.transport.http.JDKHttpConnection.getResponseCode(JDKHttpConnection.java:98) [org.eclipse.jgit-3.7.1.201504261725-r.jar:3.7.1.201504261725-r]
        at org.eclipse.jgit.util.HttpSupport.response(HttpSupport.java:168) [org.eclipse.jgit-3.7.1.201504261725-r.jar:3.7.1.201504261725-r]
        at org.eclipse.jgit.transport.TransportHttp.connect(TransportHttp.java:475) [org.eclipse.jgit-3.7.1.201504261725-r.jar:3.7.1.201504261725-r]
        ... 62 more

• My server requires proxy to access the Internet. Even after specifying system properties (http.proxyHost, http.proxyPort, http.proxyUser, http.proxyPassword, https.proxyHost, https.proxyPort, https.proxyUser, https.proxyPassword), I get the following Exception.

14:50:36,202 ERROR [org.guvnor.structure.backend.repositories.RepositoryServiceImpl] (http-0.0.0.0:8080-1) Error during create repository: java.lang.RuntimeException: https://github.com/jbossdemocentral/bpms-travel-agency-demo-repo.git: 407 Proxy Authentication Required
        at org.guvnor.structure.backend.repositories.git.GitRepositoryBuilder.createFileSystem(GitRepositoryBuilder.java:139) [guvnor-structure-backend-6.4.0.Final-redhat-6.jar:6.4.0.Final-redhat-6]
        at org.guvnor.structure.backend.repositories.git.GitRepositoryBuilder.build(GitRepositoryBuilder.java:61) [guvnor-structure-backend-6.4.0.Final-redhat-6.jar:6.4.0.Final-redhat-6]
        at org.guvnor.structure.backend.repositories.git.GitRepositoryFactoryHelper.newRepository(GitRepositoryFactoryHelper.java:63) [guvnor-structure-backend-6.4.0.Final-redhat-6.jar:6.4.0.Final-redhat-6]
        at org.guvnor.structure.backend.repositories.git.GitRepositoryFactoryHelper$Proxy$_$$_WeldClientProxy.newRepository(GitRepositoryFactoryHelper$Proxy$_$$_WeldClientProxy.java) [guvnor-structure-backend-6.4.0.Final-redhat-6.jar:6.4.0.Final-redhat-6]
        at org.guvnor.structure.backend.repositories.RepositoryFactoryImpl.newRepository(RepositoryFactoryImpl.java:61) [guvnor-structure-backend-6.4.0.Final-redhat-6.jar:6.4.0.Final-redhat-6]
...
Caused by: org.eclipse.jgit.errors.TransportException: https://github.com/jbossdemocentral/bpms-travel-agency-demo-repo.git: 407 Proxy Authentication Required
        at org.eclipse.jgit.transport.TransportHttp.connect(TransportHttp.java:516) [org.eclipse.jgit-3.7.1.201504261725-r.jar:3.7.1.201504261725-r]
        at org.eclipse.jgit.transport.TransportHttp.openFetch(TransportHttp.java:309) [org.eclipse.jgit-3.7.1.201504261725-r.jar:3.7.1.201504261725-r]
        at org.eclipse.jgit.transport.FetchProcess.executeImp(FetchProcess.java:136) [org.eclipse.jgit-3.7.1.201504261725-r.jar:3.7.1.201504261725-r]
        at org.eclipse.jgit.transport.FetchProcess.execute(FetchProcess.java:122) [org.eclipse.jgit-3.7.1.201504261725-r.jar:3.7.1.201504261725-r]
        at org.eclipse.jgit.transport.Transport.fetch(Transport.java:1138) [org.eclipse.jgit-3.7.1.201504261725-r.jar:3.7.1.201504261725-r]
        at org.eclipse.jgit.api.FetchCommand.call(FetchCommand.java:130) [org.eclipse.jgit-3.7.1.201504261725-r.jar:3.7.1.201504261725-r]
        ... 58 more