python3: convert byte to string

Part of #20

Co-authored-by: Alexander Turenko <[email protected]>

Author: ligurio

lib/tarantool_server.py

@@ -811,7 +811,7 @@ def start(self, silent=True, wait=True, wait_load=True, rais=True, args=[],
         color_log("Starting the server ...\n", schema='serv_text')
         color_log("Starting ", schema='serv_text')
         color_log(path + " \n", schema='path')
-        color_log(self.version() + "\n", schema='version')
+        color_log(str(self.version()) + "\n", schema='version')
 
         os.putenv("LISTEN", self.iproto.uri)
         os.putenv("ADMIN", self.admin.uri)