EXT-7772 FIXED Corrected button texture file name.

reviewed by Neal Orman at https://codereview.productengine.com/secondlife/r/606/

--HG--
branch : product-engine

indra/newview/skins/default/textures/textures.xml

@@ -114,7 +114,7 @@ with the same filename but different name
   <texture name="DisclosureArrow_Opened_Off" file_name="widgets/DisclosureArrow_Opened_Off.png" preload="true" />
 
   <texture name="DownArrow" file_name="bottomtray/DownArrow.png" preload="false" />
-  <texture name="DownArrow_Off" file_name="icons/DownArrow_off.png" preload="false" />
+  <texture name="DownArrow_Off" file_name="icons/DownArrow_Off.png" preload="false" />
   <texture name="Dragbar" file_name="windows/Dragbar.png" preload="false" scale.left="35" scale.top="5" scale.right="29" scale.bottom="5" />
 
   <texture name="DropDown_Disabled" file_name="widgets/DropDown_Disabled.png" preload="true" scale.left="4" scale.top="19" scale.right="99" scale.bottom="4" />