omni: omnify the overlay stub

just add a simple omni theme for now

Change-Id: I3e5c4c36253f2a8cf8a74e493e5d269a70a4c40a
diff --git a/overlaystub/res/values/arrays.xml b/overlaystub/res/values/arrays.xml
index 4d7b961..3286e6d 100644
--- a/overlaystub/res/values/arrays.xml
+++ b/overlaystub/res/values/arrays.xml
@@ -2,7 +2,6 @@
 <resources>
     <string-array name="themes">
         <item>default</item>
-        <item>electrigreen</item>
-        <item>throwback</item>
+        <item>omni</item>
     </string-array>
 </resources>