sys-fs/zfs: fix systemd related installation paths

sys-fs/zfs: fix systemd related installation paths

ebuilds intalls most systemd files into
	/usr/lib/systemd
while it should be
	/lib/systemd

qlist =sys-fs/zfs-0.7.6 | grep systemd
/usr/lib/systemd/system-preset/50-zfs.preset
/usr/lib/systemd/system/zfs-zed.service
/usr/lib/systemd/system/zfs-import-cache.service
/usr/lib/systemd/system/zfs-import-scan.service
/usr/lib/systemd/system/zfs-mount.service
/usr/lib/systemd/system/zfs-share.service
/usr/lib/systemd/system/zfs-import.target
/usr/lib/systemd/system/zfs.target
/lib/systemd/system/zfs.service < this is ok

The reason is that default values for:
--with-systemdpresetdir and
--with-systemdmodulesloaddir

point to /usr/lib/systemd

This commit overrides the location to to use
gentoo preferred /lib/systemd

Use systemd_reapply to re-create broken symlinks

Also fixes minor QA, no more --with-blkid switch
for 7.xx and live ebuilds.

Package-Manager: Portage-2.3.24, Repoman-2.3.6
Signed-off-by: Matthew Thode <prometheanfire@gentoo.org>