The attribute "enable-welcome-root" in the web subsystem in EAP 6 does not allow property substitution

Issue

• For the enable-welcome-root attribute, a variable value results in an exception.

<virtual-server name="default-host" enable-welcome-root="${jboss.web.enable.welcome.root:true}">
  <alias name="localhost"/>
  <alias name="example.com"/>
</virtual-server>

Exception:

2015-10-28 16:09:59,962 ERROR [org.jboss.as.server] (Controller Boot Thread) JBAS015956: Exception interceptΘe au dΘmarrage: org.jboss.as.controller.persistence.ConfigurationPersistenceException: JBAS014676: N'a pas pu analyser la configuration
        at org.jboss.as.controller.persistence.XmlConfigurationPersister.load(XmlConfigurationPersister.java:141) [jboss-as-controller-7.5.3.Final-redhat-2.jar:7.5.3.Final-redhat-2]
        at org.jboss.as.server.ServerService.boot(ServerService.java:336) [jboss-as-server-7.5.3.Final-redhat-2.jar:7.5.3.Final-redhat-2]
        at org.jboss.as.controller.AbstractControllerService$1.run(AbstractControllerService.java:263) [jboss-as-controller-7.5.3.Final-redhat-2.jar:7.5.3.Final-redhat-2]
        at java.lang.Thread.run(Thread.java:745) [rt.jar:1.8.0_60]
Caused by: java.lang.IllegalArgumentException
        at org.jboss.dmr.StringModelValue.asBoolean(StringModelValue.java:154) [jboss-dmr-1.2.2.Final-redhat-1.jar:1.2.2.Final-redhat-1]
        at org.jboss.dmr.ModelNode.asBoolean(ModelNode.java:262) [jboss-dmr-1.2.2.Final-redhat-1.jar:1.2.2.Final-redhat-1]
        at org.jboss.as.controller.SimpleAttributeDefinition.parse(SimpleAttributeDefinition.java:331) [jboss-as-controller-7.5.3.Final-redhat-2.jar:7.5.3.Final-redhat-2]
        at org.jboss.as.controller.SimpleAttributeDefinition.parse(SimpleAttributeDefinition.java:188) [jboss-as-controller-7.5.3.Final-redhat-2.jar:7.5.3.Final-redhat-2]
        at org.jboss.as.controller.SimpleAttributeDefinition.parseAndSetParameter(SimpleAttributeDefinition.java:243) [jboss-as-controller-7.5.3.Final-redhat-2.jar:7.5.3.Final-redhat-2]
        at org.jboss.as.web.WebSubsystemParser.parseHost(WebSubsystemParser.java:706)
        at org.jboss.as.web.WebSubsystemParser.readElement(WebSubsystemParser.java:423)
        at org.jboss.as.web.WebSubsystemParser.readElement(WebSubsystemParser.java:84)
        at org.jboss.staxmapper.XMLMapperImpl.processNested(XMLMapperImpl.java:110) [staxmapper-1.1.0.Final-redhat-3.jar:1.1.0.Final-redhat-3]
        at org.jboss.staxmapper.XMLExtendedStreamReaderImpl.handleAny(XMLExtendedStreamReaderImpl.java:69) [staxmapper-1.1.0.Final-redhat-3.jar:1.1.0.Final-redhat-3]
        at org.jboss.as.server.parsing.StandaloneXml.parseServerProfile(StandaloneXml.java:1094) [jboss-as-server-7.5.3.Final-redhat-2.jar:7.5.3.Final-redhat-2]
        at org.jboss.as.server.parsing.StandaloneXml.readServerElement_1_4(StandaloneXml.java:469) [jboss-as-server-7.5.3.Final-redhat-2.jar:7.5.3.Final-redhat-2]
        at org.jboss.as.server.parsing.StandaloneXml.readElement(StandaloneXml.java:145) [jboss-as-server-7.5.3.Final-redhat-2.jar:7.5.3.Final-redhat-2]
        at org.jboss.as.server.parsing.StandaloneXml.readElement(StandaloneXml.java:107) [jboss-as-server-7.5.3.Final-redhat-2.jar:7.5.3.Final-redhat-2]
        at org.jboss.staxmapper.XMLMapperImpl.processNested(XMLMapperImpl.java:110) [staxmapper-1.1.0.Final-redhat-3.jar:1.1.0.Final-redhat-3]
        at org.jboss.staxmapper.XMLMapperImpl.parseDocument(XMLMapperImpl.java:69) [staxmapper-1.1.0.Final-redhat-3.jar:1.1.0.Final-redhat-3]
        at org.jboss.as.controller.persistence.XmlConfigurationPersister.load(XmlConfigurationPersister.java:133) [jboss-as-controller-7.5.3.Final-redhat-2.jar:7.5.3.Final-redhat-2]

• Expressions not allowed for "enable-welcome-root" in the web subsystem for EAP 6.