Fix NPE in InCallController due to potential null call.

There is the potential for a call reference to be null due to a
reconnect to the InCallService.

Test: Manual
Bug: 37001602
Merged-In: Ia0c12e5233107d7973ea2fa112a774126bf5a097
Change-Id: Ia0c12e5233107d7973ea2fa112a774126bf5a097
1 file changed