Autotest: Add more logging to the tick.

Added a line of logging before each major step of the tick so that we
can better determine where the tick time is being used.

I put this in monitor_db.py instead of site_monitor_db.py since it does not
the proper scope to view the global variable _drone_manager.

BUG=chromium-os:33890
TEST=Made sure monitor_db ran locally and my new messages were being
printed.

Change-Id: I2c8e08bab835c4ee1a92c0a6502242048b13293a
Reviewed-on: https://gerrit.chromium.org/gerrit/31601
Commit-Ready: Simran Basi <sbasi@google.com>
Reviewed-by: Simran Basi <sbasi@google.com>
Tested-by: Simran Basi <sbasi@google.com>
diff --git a/global_config.ini b/global_config.ini
index b6da726..979713e 100644
--- a/global_config.ini
+++ b/global_config.ini
@@ -92,6 +92,7 @@
 enable_archiving: False
 copy_task_results_back: False
 copy_parse_log_back: False
+tick_debug: True
 
 
 [HOSTS]