Fix big regression with mouse events in content caused by checkin to bug 171366. Just changes NS_OK back to NS_OK as we had in original sr='d patch.

content/html/content/src/nsGenericHTMLElement.cpp

@@ -3618,7 +3618,7 @@ nsGenericHTMLElement::Focus()
     }
   }
 
-  return NS_OK;
+  return NS_ERROR_FAILURE;
 }
 
 void