Close the Drawer on BACK button if the Drawer is opened

- otherwise (if Drawer is closed), BACK should work as BACK
into the Fragments BackStack

Change-Id: Ic7f500eb77f35e2142a40e6c9e34c4e7f0ec6428
diff --git a/src/com/android/settings/SettingsActivity.java b/src/com/android/settings/SettingsActivity.java
index 00e65f2..28ff883 100644
--- a/src/com/android/settings/SettingsActivity.java
+++ b/src/com/android/settings/SettingsActivity.java
@@ -703,6 +703,15 @@
     }
 
     @Override
+    public void onBackPressed() {
+        if (mDrawerLayout.isDrawerOpen(mDrawer)) {
+            mDrawerLayout.closeDrawer(mDrawer);
+            return;
+        }
+        super.onBackPressed();
+    }
+
+    @Override
     public void onBackStackChanged() {
         setTitleFromBackStack();
     }