network: dhcp6 - fix memory leak

src/network/networkd-network.c

@@ -749,6 +749,7 @@ static Network *network_free(Network *network) {
         ordered_hashmap_free(network->dhcp_server_send_options);
         ordered_hashmap_free(network->dhcp_server_send_vendor_options);
         ordered_hashmap_free(network->ipv6_tokens);
+        ordered_hashmap_free(network->dhcp6_client_send_options);
         ordered_hashmap_free(network->dhcp6_client_send_vendor_options);
 
         return mfree(network);