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
Fix the ribbon duplication issue.
The ribbons were instantiated once in BaseStatusBar and once in PhoneStatusBar. Mend that by removing ribbons from BaseStatusBar, just like it's done in AOKP.

Change-Id: I77280ede4884d68acf8058a913e47a7e3ab55f77