Bundle event hook NPE and unresolved persisted subsystems.

Fixed NPE in bundle event hook when processing asynchronous installed events whose bundle or origin bundle revision
was null because the bundle was uninstalled.

Fixed issue where persisted subsystems were registered in the RESOLVED state before they were actually resolved.

Added bundle event hook tests for null bundle and origin bundle revisions when processing asynchronous events.

Fixed issue in itests where subsystems other than root could be returned from utility method.

git-svn-id: https://svn.apache.org/repos/asf/aries/trunk@1443681 13f79535-47bb-0310-9956-ffa450edef68