Add roles support for the script module

allows to put scripts directly in a dir within the
role:

 roles/<role>/scripts/..

Same as the copy and template module.

As requested in and closes #2969

lib/ansible/runner/action_plugins/script.py

@@ -41,6 +41,9 @@ class ActionModule(object):
         # FIXME: error handling
         args    = " ".join(tokens[1:])
         source  = template.template(self.runner.basedir, source, inject)
+        if '_original_file' in inject:
+            source = utils.path_dwim_relative(inject['_original_file'], 'scripts', source, self.runner.basedir)
+        else:
             source = utils.path_dwim(self.runner.basedir, source)
 
         # transfer the file to a remote tmp location