Remove flags.DECLARE
Remove flags.DECLARE

The cfg.ConfigOpts class has an equivalent method, so lets use that.

Change-Id: I5860230336d00d7531a0ffd255c766ff77661625

hyakuhei/cleantox,zancas/hacking,emonty/oslo-hacking,openstack-dev/hacking,openstack-dev/hacking,zancas/hacking,emonty/oslo-hacking,hyakuhei/cleantox