innodb: add space between thread name and "to exit" text

storage/innobase/log/log0log.cc

@@ -1893,7 +1893,7 @@ logs_empty_and_mark_files_at_shutdown(void)
 			"Waiting for %s to exit", thread_name);
 		if (srv_print_verbose_log && count > COUNT_INTERVAL) {
 			ib::info() << "Waiting for " << thread_name
-				   << "to exit";
+				   << " to exit";
 			count = 0;
 		}
 		goto loop;