MFC r329683: MFV r319736: 6396 remove SVM

illumos/illumos-gate@5f10ef697f250374b7b917e10961c4e02d4e3112
https://github.com/illumos/illumos-gate/commit/5f10ef697f250374b7b917e10961c4e02d4e3112

https://www.illumos.org/issues/6396

LVM = SVM = Solaris Volume Manager
dead code and not using with ZFS based platform.

Reviewed by: Igor Kozhukhov <ikozhukhov@gmail.com>
Reviewed by: Toomas Soome <tsoome@me.com>
Approved by: Hans Rosenfeld <rosenfeld@grumpf.hope-2000.org>
Author: Yuri Pankov <yuri.pankov@nexenta.com>