Establish the secure copy connection.

def establish_scp_conn(self):
        """Establish the secure copy connection."""
        ssh_connect_params = self.ssh_ctl_chan._connect_params_dict()
        self.scp_conn = self.ssh_ctl_chan._build_ssh_client()
        self.scp_conn.connect(**ssh_connect_params)
        self.scp_client = scp.SCPClient(self.scp_conn.get_transport())