Fix several CDMA call collision cases

1. Continous ringing after receiving a call waiting while in a call,
and before user answers the call waiting, the 1st call drops.  If another
MT call comes in, while it rings, it also drops, the phone will keep
ringing.

2. Data call is not re-initiated if emergency MO call collides with an MT call.

Bug: 2123287
Change-Id: I6b12a900ec60b478691544ab5326eac4952ce834