Fixing filesystem_store_metadata.json generator

Change-Id: I3d952013b1333b753a511246af33fdeee791064a
diff --git a/glance/files/filesystem_store_metadata.json_template b/glance/files/filesystem_store_metadata.json_template
index c6b85c1..0b560b9 100644
--- a/glance/files/filesystem_store_metadata.json_template
+++ b/glance/files/filesystem_store_metadata.json_template
@@ -1,8 +1,4 @@
 {%- from "glance/map.jinja" import server with context -%}
 {%- if server.filesystem_store_metadata is defined -%}
-{
-{%- for item_key, item_value in server.get('filesystem_store_metadata', {}).iteritems() %}
-  "{{ item_key }}": "{{ item_value }}"
-{%- endfor %}
-}
-{%- endif -%}
\ No newline at end of file
+{{ server.filesystem_store_metadata|json }}
+{%- endif -%}