Merged from trunk 5080:5088

Merged from trunk 5080:5088

Revert ACCEPT_LICENSE support, since license group support is a
requirement and it remain unimplemented.  This brings trunk back into
sync with the 2.1.2 branch.

For bug #155559, force depclean dep_check calls to preference installed
packages.

Use fake_vardb for cached aux_get calls.

Fix portdbapi.cpv_all() so that it actually returns a list of all
available ebuilds.

svn path=/main/branches/prefix/; revision=5089