use proper function for state destruction

Author: shaitan

library/net.c

@@ -1217,7 +1217,7 @@ struct dnet_net_state *dnet_state_create(struct dnet_node *n,
 err_out_dup_destroy:
 	dnet_sock_close(n, st->write_s);
 err_out_free:
-	free(st);
+	dnet_state_destroy(st);
 err_out_close:
 	dnet_sock_close(n, s);