bugfix : install module doesnt work unless we start the child process into a shell on Windows

lib/CLI/Modules/Modularizer.js

@@ -112,7 +112,8 @@ function installModule(CLI, module_name, cb) {
       'install', module_name, '--prefix', cst.PM2_ROOT_PATH, '--loglevel=error'
     ],{
       stdio : 'inherit',
-      async : true
+      async : true,
+			shell : cst.IS_WINDOWS
     });
 
     install_instance.on('close', finalize);