[WFLY-1636] OverrideDescriptionCombiner should add overridden children to the children and not to the attributes
WFLY-381 Add undertow support to mod_cluster subsystem.
HornetQ security manager doPrivileged() block

move all HornetQ user and roles validation into a single
AccessController.doPrivileged() block.
validateUserAndRole() is called from a thread in HornetQ own's thread
pool. Calling it inside  a doPrivileged() block ensures that the code
will not raise an AccessControlException when WildFlySecurityManager
checks the permissions.
Group all the doPrivileged blocks into a single one.
Surefire tests leave jdr_zip file because it cannot be deleted while open. Also move it to target/ and test outputDir/close.
[WFLY-1434] Enable assignment of groups for management users.

These groups will subsequently be used to assign role membership for domain management access control.