Do not return location in headers

In some cases credentials were being leaked when downloading a cached
v1 image.

Fixes bug 1135541, CVE-2013-1840

Change-Id: I3ec0a8f484fe1bdc32c3c56fce810fcef347a7f6

glance/api/middleware/cache.py

@@ -111,6 +111,9 @@ class CacheFilter(wsgi.Middleware):
 
     def _process_v1_request(self, request, image_id, image_iterator):
         image_meta = registry.get_image_metadata(request.context, image_id)
+        # Don't display location
+        if 'location' in image_meta:
+            del image_meta['location']
 
         if not image_meta['size']:
             # override image size metadata with the actual cached