QPID-5567 : Further changes to SecurityMangager

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1570239 13f79535-47bb-0310-9956-ffa450edef68
QPID-5563 : Ensure vhost is set as early as possible, on receipt of connection open

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1570242 13f79535-47bb-0310-9956-ffa450edef68