Fix a windows compilation warning from 4647 branch

src/or/ntmain.c

@@ -314,6 +314,7 @@ nt_service_main(void)
       case CMD_LIST_FINGERPRINT:
       case CMD_HASH_PASSWORD:
       case CMD_VERIFY_CONFIG:
+      case CMD_DUMP_CONFIG:
         log_err(LD_CONFIG, "Unsupported command (--list-fingerprint, "
                 "--hash-password, or --verify-config) in NT service.");
         break;