dhcp: Stop IPv4 ll state machine properly

Now the IPv4 ll address is set correctly if the ll state machine
is run more than once. The real culprit was that the ipv4ll_running
flag was not cleared when dhcp_release() was called.

Reported-by: Tim Sander <tim@krieglstein.org>

src/dhcp.c

@@ -565,24 +565,18 @@ static int dhcp_release(struct connman_dhcp *dhcp)
 	if (dhcp->timeout > 0)
 		g_source_remove(dhcp->timeout);
 
-	if (dhcp->ipv4ll_client) {
-		g_dhcp_client_stop(dhcp->ipv4ll_client);
-		g_dhcp_client_unref(dhcp->ipv4ll_client);
-	}
-
 	if (dhcp->dhcp_client) {
 		g_dhcp_client_stop(dhcp->dhcp_client);
 		g_dhcp_client_unref(dhcp->dhcp_client);
 	}
 
-	dhcp->ipv4ll_client = NULL;
 	dhcp->dhcp_client = NULL;
 
-	g_free(dhcp->ipv4ll_debug_prefix);
 	g_free(dhcp->dhcp_debug_prefix);
-	dhcp->ipv4ll_debug_prefix = NULL;
 	dhcp->dhcp_debug_prefix = NULL;
 
+	ipv4ll_stop_client(dhcp);
+
 	return 0;
 }