locator: token_metadata: added a get_topology() method

Signed-off-by: Vlad Zolotarov <vladz@cloudius-systems.com>

locator/token_metadata.hh

@@ -129,6 +129,11 @@ public:
     const std::map<token, inet_address>& get_token_to_endpoint() const {
         return _token_to_endpoint_map;
     }
+
+    topology& get_topology() {
+        return _topology;
+    }
+
     void debug_show();
 #if 0
     private static final Logger logger = LoggerFactory.getLogger(TokenMetadata.class);