UserTile : Check if profile has a photo

In the event that the profile doesn't have a photo, don't default to the
user's photo, instead show a default avatar.

Change-Id: I80de324ae1e151693cf3716bf87d39a16096ca12
Revert "Block application install from unknown sources through adb"

 * Accidental merge, not ready yet.

This reverts commit 0a8e1431a5ee7cc5b5bacd139cc76d4734963e70.