am a785a59c: am 718e0033: Merge "SIP: add SERVER_UNREACHABLE error code." into gingerbread

Merge commit 'a785a59c831256f274627f8f8eb77f9d54508916'

* commit 'a785a59c831256f274627f8f8eb77f9d54508916':
  SIP: add SERVER_UNREACHABLE error code.