LockscreenPattern : Toggle dots/error pattern visibility (2/2)

Give user ability to hide error pattern / dots.

Patchset 2 : Cleanup commit msg

Change-Id: Ifdd4615c7116f974a0a67079d58a521e84d76367

Conflicts:
	src/com/android/settings/SecuritySettings.java

Signed-off-by: iceandfire <arhamjamal@gmail.com>