SystemUI: Fix crash when resetting ShadeController views

java.lang.NullPointerException: Attempt to invoke interface method 'void com.android.systemui.shade.ShadeViewController.resetViews(boolean)' on a null object reference
	at com.android.systemui.statusbar.phone.StatusBarKeyguardViewManager.reset(StatusBarKeyguardViewManager.java:860)
	at com.android.systemui.statusbar.phone.StatusBarKeyguardViewManager.show(StatusBarKeyguardViewManager.java:662)
	at com.android.systemui.keyguard.KeyguardViewMediator.handleShow(KeyguardViewMediator.java:2780)
	at com.android.systemui.keyguard.KeyguardViewMediator.-$$Nest$mhandleShow(KeyguardViewMediator.java:0)
	at com.android.systemui.keyguard.KeyguardViewMediator$12.handleMessage(KeyguardViewMediator.java:2498)
	at android.os.Handler.dispatchMessage(Handler.java:107)
	at android.os.Looper.loopOnce(Looper.java:232)
	at android.os.Looper.loop(Looper.java:317)
	at android.app.ActivityThread.main(ActivityThread.java:8527)
	at java.lang.reflect.Method.invoke(Native Method)
	at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:555)
	at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:878)

Signed-off-by: minaripenguin <minaripenguin@users.noreply.github.com>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>