Removed trailing comma

Trailing commas don't work in old versions of IE, and are not present
in the rest of the codebase. Removed the one that remained, which
allows Google Closure compiler to compiles this code.

modules/components/Route.js

@@ -72,7 +72,7 @@ var Route = React.createClass({
 
     getUnreservedProps: function (props) {
       return withoutProperties(props, RESERVED_PROPS);
-    },
+    }
 
   },