LU-8066 lov: Move suitable variables from procfs to sysfs

LU-8066 lov: Move suitable variables from procfs to sysfs

Migrate procfs files with simple output to sysfs. Create
sysfs symlinks for target_obds.

Linux-commit : cb1debff6d8b254536ec6ff642a2bdd22c86cb85

Change-Id: I97e403694fd1aab9f70363a2961beb08c6959447
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/30960
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>