Fix #1 Ensure Stale Cleaup Timers do not periodically (return value of TimerCallback Routine)
Fix #2
  o Core was seen as the AgentXmppChannel was deleted and accessed in the TimerCallback Routine.
  o AgentXmppChannel can be deleted when a new set of XmppServers are returned by Discovery Server
  o As soon the XmppChannel goes down both AgentXmppChannel & BgpPeer ds are dissociated
Fix #3
  o No ReScheduling of Timers required as Timers are Started as part of XmppStateMachine task
    and Timer Callbacks as part of DBTask and both the tasks are exclusive, hence Timer
    Cancel() will not fail and can be used to ReStart the Timer.

    LaunchPad Id: #1385428

Change-Id: I0cf451abbe25d71abdcfaca482538a459434515a
Merge "Fix #1 Ensure Stale Cleaup Timers do not periodically (return value of TimerCallback Routine) Fix #2   o Core was seen as the AgentXmppChannel was deleted and accessed in the TimerCallback Routine.   o AgentXmppChannel can be deleted when a new set of XmppServers are returned by Discovery Server   o As soon the XmppChannel goes down both AgentXmppChannel & BgpPeer ds are dissociated Fix #3   o No ReScheduling of Timers required as Timers are Started as part of XmppStateMachine task     and Timer Callbacks as part of DBTask and both the tasks are exclusive, hence Timer     Cancel() will not fail and can be used to ReStart the Timer."