[reSIProcate] TimerCleanUp core dump.

[palladin <p-aladin@xxxxxxxxx>]

Hi all,
please consider next issue with TransactionState:
if one sends 200 ok in ClientInviteTransaction - the state becomes 
Completed and mNextTransmission becomes equal to zero. But if 
TimerCleanUp fires after this it will cause core dump in 
TransactionState.cxx:1374.

Sincerely,Taras