acc:evi: if the request failed send a missed event

In case the acc_evi_request() function was used on a failed request
(code < 300), send a missed event rather than the normal one.

Reported by Trevor Francis from 46Labs

(cherry picked from commit 18f5da0)

modules/acc/acc_logic.c

@@ -272,6 +272,17 @@ int w_acc_evi_request(struct sip_msg *rq, pv_elem_t* comment, char *foo)
 	env_set_to( rq->to );
 	env_set_comment( &accp );
 
+	if (is_cdr_acc_on(rq) && is_evi_acc_on(rq)) {
+		env_set_event(acc_cdr_event);
+	} else if (is_evi_acc_on(rq) && acc_env.code < 300) {
+		env_set_event(acc_event);
+	} else if (is_evi_mc_on(rq)) {
+		env_set_event(acc_missed_event);
+	} else {
+		LM_WARN("evi request flags not set\n");
+		return 1;
+	}
+
 	return acc_evi_request( rq, NULL, 0);
 }