[autotest] db optimization skips write to bin log

Do not write any optmization table query to binary log
so that slave won't pick it up automatically.

TEST=Run it locally
BUG=chromium:497314

Change-Id: I58c1b8322f2ad0b7647b3431036f673937061bc2
Reviewed-on: https://chromium-review.googlesource.com/275736
Reviewed-by: Dan Shi <[email protected]>
Commit-Queue: Fang Deng <[email protected]>
Tested-by: Fang Deng <[email protected]>
diff --git a/contrib/db_optimize.py b/contrib/db_optimize.py
index 8ade192..bf946ab 100755
--- a/contrib/db_optimize.py
+++ b/contrib/db_optimize.py
@@ -32,6 +32,10 @@
                '-o', database_settings['NAME'],
                '-u', database_settings['USER'],
                '-p%s' % database_settings['PASSWORD'],
+               # we want to do db optimation on each master/slave
+               # in rotation. Do not write otimize table to bin log
+               # so that it won't be picked up by slaves automatically
+               '--skip-write-binlog',
                ]
     subprocess.check_call(command)