Fix recheckwatch bug expiration.

Typo.

Change-Id: Ife995e4b3cb4c89b16df6dc7367abbd4057b3f45
Reviewed-on: https://review.openstack.org/20169
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Tested-by: Jenkins