Provide pending request TRUE only for already registered but not verified device.

Provide pending request TRUE only for already registered but not verified device.

- Problem: Pending request returns TRUE when last registered device which is not
           yet verified by plugin, even for different device.
- Cause: __uam_manager_is_request_pending() only checks for matching function
         before returning result.
- Solution: Match device_id for UAM_REQUEST_ADD_DEVICE before returning result.

Change-Id: Ie0d148f821932eb195547c47939917bb7bdbba60
Signed-off-by: Nishant Chaprana <n.chaprana@samsung.com>