Don't show external presentation until keyguard actually shows

The previous code was looking for just the display to turn off.
It should wait until keyguard is actually shown before enabling
the external presentations.

Fix for bug 11694904

Change-Id: Iebf3aa04fc094cd4e5c8f56bc771aca1e5921d04

packages/Keyguard/src/com/android/keyguard/KeyguardViewMediator.java

@@ -618,14 +618,6 @@ public class KeyguardViewMediator {
             }
         }
         KeyguardUpdateMonitor.getInstance(mContext).dispatchScreenTurndOff(why);
-
-        // This needs to run on the UI thread
-        mHandler.post(new Runnable() {
-            @Override
-            public void run() {
-                mKeyguardDisplayManager.show();
-            }
-        });
     }
 
     private void doKeyguardLaterLocked() {