Make Module.globalPaths a reference.

We need to hack the search paths of the require function so we can
load libraries from embedded applications without modifications of
node's module code.

lib/module.js

@@ -643,7 +643,7 @@ Module._initPaths = function() {
   modulePaths = paths;
 
   // clone as a shallow copy, for introspection.
-  Module.globalPaths = modulePaths.slice(0);
+  Module.globalPaths = modulePaths;
 };
 
 Module._preloadModules = function(requests) {