Don't drop up or cancel touch events

Otherwise you're gonna have a bad time.

Bug: 17113634
Change-Id: I24fa13a4379bab0cef014010058d08096abda094

packages/SystemUI/src/com/android/systemui/statusbar/phone/ObservableScrollView.java

@@ -87,7 +87,9 @@ public class ObservableScrollView extends ScrollView {
 
     @Override
     public boolean dispatchTouchEvent(MotionEvent ev) {
-        if (!mTouchEnabled) {
+        boolean isEndGuesture = (ev.getAction() == MotionEvent.ACTION_UP
+                || ev.getAction() == MotionEvent.ACTION_CANCEL);
+        if (!mTouchEnabled && !isEndGuesture) {
             return false;
         }
         return super.dispatchTouchEvent(ev);