b=716424 remove unused string kDocumentIconPath r=roc

--HG--
extra : transplant_source : %A6%C1%DE%A1%D9%28%7E9%00J%BEB%95/q%3FL%B0_%0C

browser/components/shell/src/nsGNOMEShellService.cpp

@@ -96,8 +96,6 @@ static const MimeTypeAssociation appTypes[] = {
   { "application/xhtml+xml", "xhtml xht"      }
 };
 
-static const char kDocumentIconPath[] = "firefox-document.png";
-
 // GConf registry key constants
 #define DG_BACKGROUND "/desktop/gnome/background"