Use finally block for Binder.restoreCallingIdentity

1. Use final for Binder.clearCallingIdentity() to protect not being overwritten.
2. Protect it in the finally block of the try statement to avoid missing restore the CallingIdentity as exception.

Bug: 189819183
Test: Manual test
Change-Id: I2dd4cfc1aacecb0b77fa4c82b48b24b284271779
Merged-In: I2dd4cfc1aacecb0b77fa4c82b48b24b284271779