am f7e13400: am 624d5b4e: SIP: add DisconnectCause.SERVER_ERROR

Merge commit 'f7e13400b24bdc5461e640cfb2c9cb2bbb2b6236'

* commit 'f7e13400b24bdc5461e640cfb2c9cb2bbb2b6236':
  SIP: add DisconnectCause.SERVER_ERROR