Better fix

Just use opts grains int he loader and fall back to empty dict

salt/loader.py

@@ -565,7 +565,8 @@ def render(opts, functions, states=None):
     '''
     Returns the render modules
     '''
-    pack = {'__salt__': functions}
+    pack = {'__salt__': functions,
+            '__grains__': opts.get('grains', {})}
     if states:
         pack['__states__'] = states
     ret = LazyLoader(

salt/renderers/jinja.py

@@ -367,11 +367,10 @@ def render(template_file, saltenv='base', sls='', argline='',
         raise SaltRenderError(
                 'Unknown renderer option: {opt}'.format(opt=argline)
         )
-
     tmp_data = salt.utils.templates.JINJA(template_file,
                                           to_str=True,
                                           salt=_split_module_dicts(),
-                                          grains=__opts__['grains'],
+                                          grains=__grains__,
                                           opts=__opts__,
                                           pillar=__pillar__,
                                           saltenv=saltenv,