Reconnect to In-Call if it dies.

When an In-Call Service dies, we allow it to die and stop updating it
until the ongoing calls are finished.  If the service which disconnected
was responsible for the UI, then we unbind to that service and bind to
the system-provided UI.

Bug: 21780600
Change-Id: Ibb8861aab666018ee2349e2bd0b5b96851aebf5f