[WFLY-1636] OverrideDescriptionCombiner should add overridden children to the children and not to the attributes
WFLY-381 Add undertow support to mod_cluster subsystem.
[WFLY-878] MDB DeliveryActive property

* add management operations start-delivery & stop-delivery
 (+ delivery-active runtime read-only attribute) to be able to
 start/stop delivery on the MDB resource (under
`/deployment=<deployment_name>/subsystem=ejb3/message-driven-bean=<mdb_name>`).
* by default, the MDB is started and delivery of messages occurs as soon
  as the MDB is deployed (no change from the previous behaviour)
* add support for jboss-ejb3-ext-api's @DeliveryActive to annotate the
  MDB or alternatively using the urn:delivery-active:1.0 element in
  jboss-ejb3.xml deployment descriptor
* add support for DeliveryActive activation config property (for
  backwards compatibility and migration) but logs a deprecation
  warning if it is used
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.
[WFLY-1434] Enable assignment of groups for management users.

These groups will subsequently be used to assign role membership for domain management access control.
Surefire tests leave jdr_zip file because it cannot be deleted while open. Also move it to target/ and test outputDir/close.