Remove dependency on sysutils/checkpassword. In the default install it's
used only for qmail-pop3d, which is likely not being used much anymore.
Other installs might need a different implementation of checkpassword
anyhow. And this implementation is not (yet?) in the public domain, so
it's blocking us from publishing binary packages of qmail.

Unless (until?) sysutils/checkpassword becomes "public-domain", it
remains under "djb-nonlicense". If you continue to need it, since you've
already accepted the nonlicense, simply install it directly.

I believe this package and all its remaining dependencies are now in
DEFAULT_ACCEPTABLE_LICENSES. Bump PKGREVISION.

(schmonz)