Bug 590258 - Reformat x86-on-x86_64 part of Linux UA string. r+sr=jst, a=beta5+

netwerk/protocol/http/nsHttpHandler.cpp

@@ -785,7 +785,7 @@ nsHttpHandler::InitUserAgentComponents()
             // to differentiate this from someone running 64-bit code
             // on x86_64..
 
-            buf += " i686 (x86_64)";
+            buf += " i686 on x86_64";
         } else {
             buf += ' ';