Check if fragment transaction is empty before attempting to remove it

Change-Id: I08591c89559d33fee30ac2934fdbcc30637147da

PrivacyGuard fragment fix - change from empty check to isDestroyed check

Change-Id: I52fe44b7446cd16793df6ac9cdbe31e2ddd70210

PrivacyGuardManager: Reduce calls to getFragmentManager

Change-Id: I74f07a58b09cf0e9114d0c1c56e9a97d55ab0900