CameraBase: Don't return an sp<> by reference

If the server dies, the binder death callback clears out
the global camera service sp<>, and any current references to it
will become quite unhappy.

Test: Camera CTS passes
Bug: 31992879
Change-Id: I2966bed35d0319e3f26e3d4b1b8dc08006a22348
(cherry picked from commit 4b49489c12e6862e9a320ebcb53872e809ed20ec)
2 files changed