Fix a bug where the sip unregister CLI command did not completely unregister the peer.

(closes issue #15118)
Reported by: alecdavis
Patches:
      chan_sip_unregister.diff2.txt uploaded by alecdavis (license 585)


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@196721 65c4cc65-6c06-0410-ace0-fbb531ad65f3