keep homebrew updated on osx

Refs: #323
servo · bors-servo · May 5, 2016 · May 4, 2016 · May 4, 2016 · 445fb53d9c03a5d059955987e596818228aac500
commit 445fb53d9c03a5d059955987e596818228aac500
diff --git a/common/init.sls b/common/init.sls
@@ -4,6 +4,9 @@ python2:
   pkg.installed:
     - pkgs:
       - python
+    {% if grains['os'] == 'MacOS' %}
+    - refresh: True
+    {% endif %}
 
 {% if grains['os'] == 'Ubuntu' %}
 python2-dev: