Don't compress log help files.

* modules/openstack_project/files/log_archive_maintenance.sh: The
log compression script no longer attempts to compress files stored
in the help subdirectory of the site document root.

Change-Id: I1db1dead0608c10b71dd3d91c1fedc2d7cc06926
Reviewed-on: https://review.openstack.org/34263
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Monty Taylor <mordred@inaugust.com>
Approved: Monty Taylor <mordred@inaugust.com>
Tested-by: Jenkins