Now, if a release is specified, instead of just looking for a directory
with the same name as the release, try several possible directories (each
suffixed with the release name) relative to the base directory including
".", "releases/MACHINE", "snapshots/MACHINE", and each of those prefixed
with "pub/FreeBSD/". This will allow us to remove the evil symlinks under
pub/FreeBSD/releases/MACHINE/ to the snapshots on the ftp site.