Adding progaurd exception for click handler that's only
called by reflection.

Change-Id: Idac09b60605fda74334f5a2157b7369207cc7ef2
diff --git a/proguard.flags b/proguard.flags
index 607c14b..e7d00c6 100644
--- a/proguard.flags
+++ b/proguard.flags
@@ -5,6 +5,7 @@
   public void onClickSearchButton(android.view.View);
   public void onClickConfigureButton(android.view.View);
   public void onClickAllAppsButton(android.view.View);
+  public void onClickRotateButton(android.view.View);
 }
 
 -keep class com.android.launcher2.CellLayout {