Heat template network discovery

While this issue appears fixed for any localhost calls (https://bugs.launchpad.net/ossa/+bug/1606500), Horizon/Heat still returns additional information when an IP is provided. For instance, when using http://x.x.x.x:22, if the IP is reachable, the SSH banner is returned. This works for any IP:port combination beyond localhost.

It appears as though it should only return "Template format version not found". This occurs when using the URL source, as well as when using direct input and providing the source in the user_data / get_file format.