Fix DeviceAdminReceiverTest NPE

This unit test threw a NPE because getting the extras
requires a pending result in the receiver which can
only be set by a private API. The test could be changed
to be a functional test to test this bit, but for now
just remove these lines.

Change-Id: I992b7813353c7f8e8f84cf5c8bc3898d1b1a9600