Adjust error message for shot uploading; leaking URL seemed wrong, and it wasn't clear what the request was trying to accomplish.
Adjust error message for shot uploading; leaking URL seemed wrong, and it wasn't clear what the request was trying to accomplish.

mozilla-services/screenshots,mozilla-services/pageshot,fzzzy/pageshot,mozilla-services/pageshot,mozilla-services/screenshots,mozilla-services/screenshots,mozilla-services/pageshot,mozilla-services/screenshots,fzzzy/pageshot,fzzzy/pageshot,mozilla-services/pageshot,fzzzy/pageshot