Fix typo with log_config in zuul.conf-sample
Fix typo with log_config in zuul.conf-sample

Change-Id: Ieda682233843b4500e8d59d91ac24b36dfd172dd
Signed-off-by: Paul Belanger <b4265d8fef626f73eff739ef4ffce9d45b30eddd@polybeacon.com>
Reviewed-on: https://review.openstack.org/14433
Approved: James E. Blair <e81a02a9d6405977f63a769d9f6ec8ed9d924325@inaugust.com>
Reviewed-by: James E. Blair <e81a02a9d6405977f63a769d9f6ec8ed9d924325@inaugust.com>
Tested-by: Jenkins

devdattakulkarni/zuul_messaging,devdattakulkarni/zuul_messaging,wikimedia/integration-zuul,wikimedia/integration-zuul,gooddata/zuul,wikimedia/integration-zuul,gooddata/zuul,gooddata/zuul,wikimedia/integration-zuul,gooddata/zuul,devdattakulkarni/zuul_messaging,gooddata/zuul