Fix black bar in metacity titlebar

Author: Elbullazul

metacity-1/metacity-theme-3.xml

@@ -108,6 +108,7 @@
 	<distance name="bottom_height" value="0" />
 	<distance name="title_vertical_pad" value="0" />
 	<border name="title_border" left="10" right="10" top="0" bottom="0" />
+	<border name="button_border" left="0" right="0" top="0" bottom="0"/>
     <distance name="button_height" value="0"/>
 </frame_geometry>