[eclass] Improve add_frameworks_dep minimum version handling.

Packages in kde-frameworks depending on other frameworks should require a
version equal or greater to their own. Packages in all other categories should
require some minimal version (like KDE_MINIMAL from KDE4).

This solves an issue where live Plasma 5 packages require live Frameworks
packages, when really a recent release works fine.
[eclass] Punt bogus deps again, but for kde-base only.

It might be possible to refine this further later.