Unable to add new feature repository to JBoss Fuse

Issue

I have tried adding a new feature repository to JBoss Fuse, however it fails with the following error:

2016-05-25 11:34:50,719 | ERROR | l Console Thread | Console                          | 38 - org.apache.karaf.shell.console - 2.4.0.redhat-621084 | Exception caught while executing command
org.apache.karaf.shell.console.MultiException: Unable to add repositories:
        Repository spec is empty string.
        at org.apache.karaf.shell.console.MultiException.throwIf(MultiException.java:91)
        at org.apache.karaf.features.command.AddUrlCommand.doExecute(AddUrlCommand.java:47)
        at org.apache.karaf.features.command.FeaturesCommandSupport.doExecute(FeaturesCommandSupport.java:41)
        at org.apache.karaf.shell.console.OsgiCommandSupport.execute(OsgiCommandSupport.java:38)
        at org.apache.felix.gogo.commands.basic.AbstractCommand.execute(AbstractCommand.java:35)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)[:1.7.0_55]
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)[:1.7.0_55]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)[:1.7.0_55]
        at java.lang.reflect.Method.invoke(Method.java:606)[:1.7.0_55]
        at org.apache.aries.proxy.impl.ProxyHandler$1.invoke(ProxyHandler.java:54)[19:org.apache.aries.proxy.impl:1.0.4]
        at org.apache.aries.proxy.impl.ProxyHandler.invoke(ProxyHandler.java:119)[19:org.apache.aries.proxy.impl:1.0.4]
        at org.apache.karaf.shell.console.commands.$BlueprintCommand1004628333.execute(Unknown Source)[38:org.apache.karaf.shell.console:2.4.0.redhat-621084]
        at org.apache.felix.gogo.runtime.CommandProxy.execute(CommandProxy.java:78)[38:org.apache.karaf.shell.console:2.4.0.redhat-621084]
        at org.apache.felix.gogo.runtime.Closure.executeCmd(Closure.java:477)[38:org.apache.karaf.shell.console:2.4.0.redhat-621084]
        at org.apache.felix.gogo.runtime.Closure.executeStatement(Closure.java:403)[38:org.apache.karaf.shell.console:2.4.0.redhat-621084]
        at org.apache.felix.gogo.runtime.Pipe.run(Pipe.java:108)[38:org.apache.karaf.shell.console:2.4.0.redhat-621084]
        at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:183)[38:org.apache.karaf.shell.console:2.4.0.redhat-621084]
        at org.apache.felix.gogo.runtime.Closure.execute(Closure.java:120)[38:org.apache.karaf.shell.console:2.4.0.redhat-621084]
        at org.apache.felix.gogo.runtime.CommandSessionImpl.execute(CommandSessionImpl.java:92)[38:org.apache.karaf.shell.console:2.4.0.redhat-621084]
        at org.apache.karaf.shell.console.jline.Console.run(Console.java:197)[38:org.apache.karaf.shell.console:2.4.0.redhat-621084]
        at org.apache.karaf.shell.console.jline.DelayedStarted.run(DelayedStarted.java:79)[38:org.apache.karaf.shell.console:2.4.0.redhat-621084]
Caused by: shaded.org.ops4j.lang.NullArgumentException: Repository spec is empty string.
        at shaded.org.ops4j.lang.NullArgumentException.validateNotEmpty(NullArgumentException.java:109)
        at org.ops4j.pax.url.mvn.internal.config.MavenRepositoryURL.<init>(MavenRepositoryURL.java:94)
        at org.ops4j.pax.url.mvn.internal.config.MavenConfigurationImpl.getRepositories(MavenConfigurationImpl.java:315)
        at org.ops4j.pax.url.mvn.internal.AetherBasedResolver.selectRepositories(AetherBasedResolver.java:349)
        at org.ops4j.pax.url.mvn.internal.AetherBasedResolver.resolve(AetherBasedResolver.java:523)
        at org.ops4j.pax.url.mvn.internal.AetherBasedResolver.resolve(AetherBasedResolver.java:506)
        at org.ops4j.pax.url.mvn.internal.AetherBasedResolver.resolve(AetherBasedResolver.java:481)
        at org.ops4j.pax.url.mvn.internal.Connection.getInputStream(Connection.java:123)
        at org.apache.karaf.features.internal.FeatureValidationUtil.validate(FeatureValidationUtil.java:55)
        at org.apache.karaf.features.internal.FeaturesServiceImpl.validateRepository(FeaturesServiceImpl.java:231)
        at org.apache.karaf.features.internal.FeaturesServiceImpl.internalAddRepository(FeaturesServiceImpl.java:273)
        at org.apache.karaf.features.internal.FeaturesServiceImpl.addRepository(FeaturesServiceImpl.java:253)
        at org.apache.karaf.features.command.AddUrlCommand.doExecute(AddUrlCommand.java:42)