the advantage that KDE applications work when logging in via ssh,
and that you don't need to logout to have KDE upgrades take effect.
On the downside, since the various KDE packages and shared-mime-info
all have their own MIME databases, if we put them in one symlink
tree (systemPath), we need to rerun update-mime-database on the
symlink tree. Also, systemPath is getting very large.
svn path=/nixos/branches/fix-style/; revision=14191