Camera service: Don't crash if the camera HAL dies mid-use.

Check for transaction errors in all calls to the HIDL interface;
return DEAD_OBJECT consistently if a transaction error occurs.

Test: Camera CTS does not regress; killing camera HAL does not kill camera service.
Bug: 37748853
Change-Id: Iab3ad08376e164db340f8f29c3cfc7fdf261cc00