Fix pedantic mode of chan_sip to only check the

Fix pedantic mode of chan_sip to only check the
remote tag of an endpoint once a dialog has
been confirmed. Up until that point, it is possible
and legal for the far-end to send provisional
responses with a different To: tag each time. With
this patch applied, these provisional messages
will not cause a matching problem.

(closes issue #11536)
Reported by: ibc
Patches:
      11536v2.patch uploaded by putnopvut (license 60)

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@141809 65c4cc65-6c06-0410-ace0-fbb531ad65f3