service : Fix put data on null pointer

service : Fix put data on null pointer

when using ConnectService of Manager interface a segfault arises due
to a null pointer.

in __connman_service_create_and_connect:

	[...]
	service = lookup_by_identifier(name);

	if (service != NULL)
		goto done;

	network = create_hidden_wifi(device, ssid, mode, security);
	if (network != NULL) {
		connman_network_set_group(network, group);
		service->network_created = TRUE;
	}
	[...]
in this part "service" is null