am 8544560c: SipPhone: fix missing-call DisconnectCause feedback

Merge commit '8544560ccc43de7ff49d91866f461f5572f0b147' into gingerbread-plus-aosp

* commit '8544560ccc43de7ff49d91866f461f5572f0b147':
  SipPhone: fix missing-call DisconnectCause feedback