python: Convert percent formatting to Python 3.6 f-strings.

Generated by pyupgrade --py36-plus.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

scripts/nagios/check-rabbitmq-consumers

@@ -81,7 +81,5 @@ for queue_name in consumers.keys():
     else:
         status = 0
     with open(state_file_tmp, "w") as f:
-        f.write("%s|%s|%s|queue %s has %s consumers, needs %s\n" % (
-            now, status, states[status], queue_name,
-            consumers[queue_name], target_count))
+        f.write(f"{now}|{status}|{states[status]}|queue {queue_name} has {consumers[queue_name]} consumers, needs {target_count}\n")
     os.rename(state_file_tmp, state_file_path)

scripts/nagios/cron_file_helper.py

@@ -32,4 +32,4 @@ def nagios_from_file(results_file: str) -> Tuple[int, str]:
             state = pieces[2]
             data = pieces[3]
 
-    return (ret, "%s: %s" % (state, data))
+    return (ret, f"{state}: {data}")