sys-fs/zfs: update live ebuild

sys-fs/zfs: update live ebuild

remove *.la files if no static-libs requested

clarify genkernel encryption support with genkernel-4

remove obsolete zfs initscript checks, those were here since cvs times.
Those initscripts long gone and systems already migrated to new scripts.

remove obsolete systemd-reenable calls, those were needed with earlier
versions incorrectly installing systemd units to wrong location.
it has been more than a year since those versions are gone.

Bug: https://bugs.gentoo.org/647688
Package-Manager: Portage-2.3.71, Repoman-2.3.17
Signed-off-by: Georgy Yakovlev <gyakovlev@gentoo.org>