Close stream.

linux/system/doc.sls

@@ -21,7 +21,7 @@ linux_system_doc_validity_check:
   pkg.installed:
   - name: python-yaml 
   cmd.wait:
-  - name: python -c "import yaml; stream = file('/etc/salt/grains.d/sphinx', 'r'); yaml.load(stream)"
+  - name: python -c "import yaml; stream = file('/etc/salt/grains.d/sphinx', 'r'); yaml.load(stream); stream.close()"
   - require:
     - pkg: linux_system_doc_validity_check
   - watch: