Keyguard: fix statusbar lags when default widget shown.

When statusbar became expanded KeyguardStatusView receives
onKeyguardVisibilityChanged callback and refreshes ClockView.
Because it receives more than one call and every time it reads
new values from resources it cause lags in opening statusbar panel.

Replace this code with BroadcastReceiver and ContentObserver to
refresh it only in case something was changed.

Change-Id: If0dbc1db059536806852661931cb2e6436f2acf4
Keyguard: fix not shown overlay widgets from system

google derp....due that if widgets are disabled current AOSP
code just add the default widget. Then checkAppWidgetConsistency()
detects a widget which was added and the complete method is non op.
Whatever lets handle the whole process over checkAppWidgetConsistency()
on widget disabled it tries to bind the default widget over overlay if
this is without sucess it falls back to the system one.
Safemode falls always to the system one

This fixes as well an issue that the saved default id in LockPatternUtils
is not reseted back to default if all widgets were deleted from the user.
Based on an old patch from danesh. Thanks for the
suggestion

Change-Id: Ic8543e0b5e83114e57942225935870f45deda97e
Merge "Keyguard: fix not shown overlay widgets from system" into kitkat
Merge "Keyguard: fix statusbar lags when default widget shown." into kitkat