-fixed some transaction state memory leaks in DUM - resulting from race conditions in DUM Cancel handling
 -Rece#1 - DialogSet.cxx - if Dialogset is still around, but dialog is gone (potentially BYE'd).
           Need to respond to CANCEL in order for transaction in stack to go away
 -Race#2 - ServerAuthManager - if we are waiting for an async user auth info to arrive on an INVITE with
           credentials when a CANCEL arrives, we did not correctly respond to the CANCEL
         - DialogUsageManager - needed a change to handle the User Auth info arriving after destroying the 
           feature chain due to a CANCEL 


git-svn-id: https://svn.resiprocate.org/rep/resiprocate/main@10876 ddefafc4-47db-0310-ae44-fa13212b10f2