Explicitly set a black background behind the video surface

This overrides the color set by the theme (like the ugly gradient in
ICS).

vlc-android/res/layout/player.xml

 <?xml version="1.0" encoding="utf-8"?>
 <FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="fill_parent"
-    android:layout_height="fill_parent" >
+    android:layout_height="fill_parent"
+    android:background="#000" >
 
     <SurfaceView
         android:id="@+id/player_surface"
@@ -162,4 +163,4 @@
             android:background="@drawable/ic_lock" />
     </RelativeLayout>
 
-</FrameLayout>
\ No newline at end of file
+</FrameLayout>