Custom options need to be a file passed via -F because we want
to specify options for both ssh and scp. They don't have a compatible
set of CLI options but both take -F.

This supercedes 53f5ba49 ; I had only deployed SSHOPTIONS for one host which
I've updated.

This also removes the SSHPORT option, which had only been used in the config
for one host which I've updated.