-ensure we can send a 100 Trying for NonInviteTransaction retransmissions after one
 has already been sent - previously an assert would be triggered - thanks to 
 Krister Jarl for finding this

git-svn-id: https://svn.resiprocate.org/rep/resiprocate/main@10127 ddefafc4-47db-0310-ae44-fa13212b10f2