Run an ssh command using the configured user/server values.

def ssh(self, *command):
        """Run an ssh command using the configured user/server values."""
        if self.args.user:
            ssh_spec = '{0}@{1}'.format(self.args.user, self.args.server)
        else:
            ssh_spec = self.args.server

        return self.sh('ssh', ssh_spec, *command)