Navring: Fix shortcut for uninstalled app

Fix NPE when the user uninstalls an app that was assigned to a navring
shortcut before.

Change-Id: I3f02fca73cb30e2edbb35d089ad127b35d8233c0
Merge branch 'cyanogenmod' into cm-10.1
Fix navigation bar not showing when switching from tablet to phone ui

Change-Id: I57bb0a0a9a365779f62f75d3f8138168771ce3bd