Add missing break statement

* User probably doesn't intend to add additional participants to a
  conversation with someone they wish to blacklist ;)

Change-Id: If0853e2b1a5a9b89b6dc98297ca0f0bdadf9252c
Merge "Add missing break statement" into cm-10.2
Merge remote-tracking branch 'cm/cm-10.2' into cm-10.2