Fixing bug 5011917 - clearing refernce to old folders from FolderInfo

-> Also, ensured that unbind() gets called on all ItemInfos on rotate

Change-Id: I869b68fcae5c66702ec204596f5ecabdc7a32df7
diff --git a/src/com/android/launcher2/FolderInfo.java b/src/com/android/launcher2/FolderInfo.java
index b5b5b29..3ae31d2 100644
--- a/src/com/android/launcher2/FolderInfo.java
+++ b/src/com/android/launcher2/FolderInfo.java
@@ -99,6 +99,12 @@
         }
     }
 
+    @Override
+    void unbind() {
+        super.unbind();
+        listeners.clear();
+    }
+
     interface FolderListener {
         public void onAdd(ShortcutInfo item);
         public void onRemove(ShortcutInfo item);