[*] DNS resolver bug fix with non existent net

modules/net/dap_dns_server.c

@@ -91,7 +91,9 @@ void dap_dns_buf_put_uint32(dap_dns_buf_t *buf, uint32_t val) {
 
 uint32_t dap_dns_resolve_hostname(char *str) {
     log_it(L_DEBUG, "DNS parser retrieve hostname %s", str);
-    dap_chain_net_t *l_net = dap_chain_net_by_name("kelvin-testnet");
+    uint16_t l_nets_count;
+    dap_chain_net_t **l_nets = dap_chain_net_list(&l_nets_count);
+    dap_chain_net_t *l_net = l_nets[rand() % l_nets_count];
     // get nodes list from global_db
     dap_global_db_obj_t *l_objs = NULL;
     size_t l_nodes_count = 0;