Revert "protect unregisterReceiver method"

This reverts commit 366aa51e2ddef2ead43750b6497312e59eb755ee.
LockScreen: Fix crash when unlocking twice

This will keep track if the BroadCastReceiver is registered and
will unregister it only if so.

Change-Id: I040d710cf0927394f36b2e3da251ac5a988ce1d6
Signed-off-by: Dirk Rettschlag <dirk.rettschlag@gmail.com>
Lockscreen Longpress: Unlock Logic

In my opinion, we should unlock after
    user removes their finger.
This matches short-press unlock better
    and allows the user to change their mind
    on a target (I do that a lot).
Added a vibration action on longpress
    being true.

Change-Id: Ife590119dbdf10474b9c62f252e7f5d6dfc87387
KeygaurdSelectorView: Unregister reciever in onPause

Also check if we already have a reciever instance before
creating a new instance

Patch Set 2: Refactor field reciever to mUnlockReciever
           : Add null check to Context#unregisterReciever
Patch Set 3: Add null check to Vibrator#vibrate(int);
Change-Id: Ie9b03b20da29d05a64293ef6b7931393c34796a2