Skip certain tags for metapackages

Skip extended-description-is-probably-too-short,
depends-on-packaging-dev and empty-binary-package for metapackages
(Section: metapackages, transtional packages etc.).

Technically, depends-on-packaging should not be omitted for
transitional packages, but it seems unlikely to occur by chance.

Signed-off-by: Niels Thykier <niels@thykier.net>