remote: fix regression connecting to remote session daemon

remote: fix regression connecting to remote session daemon

While we couldn't historically connect to the remote session daemon
automatically, we do allow the user to set an explicit socket path
to enable the connections to work. This ability was accidentally
lost in

  commit f8ec7c842df9e40c6607eae9b0223766cb226336
  Author: Daniel P. Berrangé <berrange@redhat.com>
  Date:   Wed Jul 8 17:03:38 2020 +0100

    rpc: use new virt-ssh-helper binary for remote tunnelling

We need to force use of 'netcat' when a 'socket' path is given in
the URI parameters.

Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>