Adding support for (multiple) swift backends (#7)

* Add support for swift_store_config_file setting and generating the references based on pillar data.

* Adding pillar example data for multiple swift references

* Updating test cases to use mitaka files
diff --git a/tests/pillar/single_swift.sls b/tests/pillar/single_swift.sls
index 97d4fdd..4fb6629 100644
--- a/tests/pillar/single_swift.sls
+++ b/tests/pillar/single_swift.sls
@@ -1,7 +1,7 @@
 glance:
   server:
     enabled: true
-    version: liberty
+    version: mitaka
     workers: 1
     database:
       engine: mysql