Expire docs-drafts more aggressively

* modules/openstack_project/files/log_archive_maintenance.sh: The
majority of the content in drafts is not gzip-compressed files, and
it should be safe to just remove everything old besides what's under
lost+found anyway.

Change-Id: Ib41f6f478e216af45f8fe560651735fb0a77cdf4
Merge "Expire docs-drafts more aggressively"