NPE fix

bug # 3429886
diff --git a/src/com/android/launcher2/Launcher.java b/src/com/android/launcher2/Launcher.java
index 6f40748..745ae2e 100644
--- a/src/com/android/launcher2/Launcher.java
+++ b/src/com/android/launcher2/Launcher.java
@@ -1971,7 +1971,9 @@
      * Re-listen when widgets are reset.
      */
     private void onAppWidgetReset() {
-        mAppWidgetHost.startListening();
+        if (mAppWidgetHost != null) {
+            mAppWidgetHost.startListening();
+        }
     }
 
     /**