PackageManager: Limit the platform-key protection to test-keys builds

This block (change I7390b3bdf5289411f7a335c69635bed9f74bbfb3) is intended
to protect the system from abuse of well-known keys. That's not the case
if the system is signed with dev or release keys.

Change-Id: Ifb66f775dd28c577447634ae177442732a18b592
Revert the previous 5 app ops commits.  Broke google setup.
Signed-off-by: scott <scott@ubuntu.com>

Change-Id: I4e92dbf40dc0155acedc40c3614c04ce28ab8e19