This CL removes the port arguments for both tools.
The port argument can also be specified via the ssh-command and
scp-command flags. In fact, if a port is specified by both port flags
and ssh/scp commands, they interfere with each other. For ssh, the one
specified in ssh-command wins. For scp, the one specified in
scp-command wins. To fix this, one would have to parse scp-command and
remove the port arg there. Or we could just remove the ssh-port arg.
This is what this CL does. Note that if you need a custom port, it's
very likely that you also have to define custom ssh and scp commands.
