Fix issue #11536426: Permission denied when trying to launch...

...an activity from a notification

We don't remove pending intents when updating an app, which is necessary
to keep app widgets and other things working.  However, when uninstalling
an app, we should clear out all of its pending intents.

Change-Id: I4b2980f407dbae6c2f4700ca8bc08f299f0a6dca