Fix issue where Workspace scrolling doesn't work

=> The WorkspaceTouchListener was relying on receiving TOUCH_DOWN in order to
   clear its state. This is not guaranteed; ie. when touches begin above
   children of the workspace (icons or widgets)

=> Any invocation of the Workspace long press menu would trigger this issue
   and it would persist until a touch went directly onto the Workspace in a
   location without any children.

Bug 132298752

Change-Id: Id8617baaa1ce59dc84758a7c82049329323b04cc

src/com/android/launcher3/touch/WorkspaceTouchListener.java

@@ -99,7 +99,6 @@ public class WorkspaceTouchListener extends GestureDetector.SimpleOnGestureListe
                 handleLongPress = mTempRect.contains((int) ev.getX(), (int) ev.getY());
             }
 
-            cancelLongPress();
             if (handleLongPress) {
                 mLongPressState = STATE_REQUESTED;
                 mTouchDownPoint.set(ev.getX(), ev.getY());
@@ -148,6 +147,10 @@ public class WorkspaceTouchListener extends GestureDetector.SimpleOnGestureListe
             }
         }
 
+        if (action == ACTION_UP || action == ACTION_CANCEL) {
+            cancelLongPress();
+        }
+
         return result;
     }