am 907f6f1d: Merge "Fix SipSessionGroup from throwing ConcurrentModificationException" into gingerbread

Merge commit '907f6f1d7d13531015b545861b93e1607d253cfd' into gingerbread-plus-aosp

* commit '907f6f1d7d13531015b545861b93e1607d253cfd':
  Fix SipSessionGroup from throwing ConcurrentModificationException