Fix #29737133 : content-trigger jobs not running properly

When removing the ContentObserver wrapper from our internal
bookkeeping we were using the wrong key.  That led to future
re-registrations thinking they were reusing a currently-
registered observers, but instead never getting onChange()
notifications.

Change-Id: Id3111db057ae63194049d7d48d45b75be6bb0000
1 file changed