dhtproxy: fix restinio start w/o dhtlogger

tools/dhtnode.cpp

@@ -537,6 +537,8 @@ main(int argc, char **argv)
                 context.logger = log::getFileLogger(params.logfile);
             else
                 context.logger = log::getStdLogger();
+        } else {
+            context.logger = nullptr;
         }
 
         node->run(params.port, config, std::move(context));
@@ -551,7 +553,7 @@ main(int argc, char **argv)
 #endif
         if (params.proxyserver != 0) {
 #ifdef OPENDHT_PROXY_SERVER
-            proxies.emplace(params.proxyserver, std::unique_ptr<DhtProxyServer>(new DhtProxyServer(node, params.proxyserver, params.pushserver, *context.logger)));
+            proxies.emplace(params.proxyserver, std::unique_ptr<DhtProxyServer>(new DhtProxyServer(node, params.proxyserver, params.pushserver, context.logger)));
 #else
             std::cerr << "DHT proxy server requested but OpenDHT built without proxy server support." << std::endl;
             exit(EXIT_FAILURE);