Make sure to clear pending spec

So when it gets out of sync it only fails once

Change-Id: If494fddfcbcb0145e2db1caa3b7612d8452c70d4

packages/SystemUI/src/com/android/systemui/recents/views/RecentsTransitionHelper.java

@@ -190,6 +190,9 @@ public class RecentsTransitionHelper {
                 };
             }
             try {
+                synchronized (this) {
+                    mAppTransitionAnimationSpecs = SPECS_WAITING;
+                }
                 WindowManagerGlobal.getWindowManagerService()
                         .overridePendingAppTransitionMultiThumbFuture(transitionFuture,
                                 callback, true /* scaleUp */);