[RFC] emi2 driver login behaviour

My EMI2 provider from time to time leaves my connections in a zombie state:
althought I closed it, they see them as already open (they have problems
with their soft I guess). The result is that when I try to login again they
reject me with a "number of sessions exceeded" reason.

When that happens, the EMI2 driver gives up and does a shutdown. This is the
relevant code:

	    emimsg = make_emi60(privdata);
	    emi2_emimsg_send(conn, server, emimsg);
	    emimsg_destroy(emimsg);
	    result = wait_for_ack(privdata, server, 60, 30);
	    if (result == -2) {
		/* Are SMSCs going to return any temporary errors? If so,
		 * testing for those error codes should be added here. */
		error(0, "smsc_emi2: Server rejected our login, giving up");
		conn->why_killed = SMSCCONN_KILLED_WRONG_PASSWORD;
		conn_destroy(server);
		return NULL;
	    }
	    else if (result == 0) {
		error(0, "smsc_emi2: Got no reply to login attempt "
		      "within 30 s");
		conn_destroy(server);
		continue;
	    }
	    else if (result == -1) { /* Broken connection, already logged */
		conn_destroy(server);
		continue;
	    }

Eventually, the sessions they have will die and I will be able to login.

Others drivers will sleep and try again. I think this is the way to go, as
Kannel is meant to run 24/7 mostly unattended. The modifications needed to
do that are trivial. I have done it with good results.

What do you think?

Angel Fradejas.