channels/chan_sip: Add improved support for 4xx error codes

This patch adds support for 414, 493, 479, and a stray 400 response in REGISTER
response handling. This helps interoperability in a number of scenarios.

Review: https://reviewboard.asterisk.org/r/3437

patches:
  rb3437.patch uploaded by oej (License 5267)
........

Merged revisions 426599 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 426600 from http://svn.asterisk.org/svn/asterisk/branches/11
........

Merged revisions 426601 from http://svn.asterisk.org/svn/asterisk/branches/12
........

Merged revisions 426602 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@426603 65c4cc65-6c06-0410-ace0-fbb531ad65f3