tornado: Disable routine logging in dev.

This creates a lot of logging noise, and also causes confusion
for new contributors when something isn't working as they expect
and they aren't sure if this message is normal or an error.

zerver/tornado/event_queue.py

@@ -412,6 +412,7 @@ def gc_event_queues():
     # not have a current handler.
     do_gc_event_queues(to_remove, affected_users, affected_realms)
 
+    if settings.PRODUCTION:
         logging.info(('Tornado removed %d idle event queues owned by %d users in %.3fs.' +
                       '  Now %d active queues, %s')
                      % (len(to_remove), len(affected_users), time.time() - start,

zerver/tornado/ioloop_logging.py

@@ -70,7 +70,7 @@ class InstrumentedPoll(object):
             in_poll = sum(b-a for a, b in self._times)
             if total > 0:
                 percent_busy = 100 * (1 - in_poll / total)
-                if settings.PRODUCTION or percent_busy > 20:
+                if settings.PRODUCTION:
                     logging.info('Tornado %5.1f%% busy over the past %4.1f seconds'
                                  % (percent_busy, total))
                     self._last_print = t1