fixed DHT state save bug for node-id

ChangeLog

@@ -102,6 +102,7 @@ release 0.14.7
 	* back-ported some fixes for building with no exceptions
 	* fixed create_torrent when passing in a path ending with /
 	* fixed move_storage when source doesn't exist
+	* fixed DHT state save bug for node-id
 
 release 0.14.6
 

src/kademlia/dht_tracker.cpp

@@ -569,9 +569,7 @@ namespace libtorrent { namespace dht
 				ret["nodes"] = nodes;
 		}
 
-		char node_id[41];
-		to_hex((char*)&m_dht.nid()[0], 20, node_id);
-		ret["node-id"] = node_id;
+		ret["node-id"] = m_dht.nid().to_string();
 		return ret;
 	}