Assume http upload if ssh_info cannot be parsed

When uploading a change for review, we sometimes request /ssh_info to
get the correct port number for uploading via ssh (regardless of
whether or not we intend to upload over ssh).

If we have trouble accessing /ssh_info (for authentication reasons,
etc), we now press on under the assumption that we will upload via http
instead of aborting.

Change-Id: Ica6bbeac1279e89424a903529649b7f4af0b6937