LU-13719 lov: doesn't check lov_refcount

LU-13719 lov: doesn't check lov_refcount

In lov_cleanup, the check of each OSC is protected by
lov_tgt_getrefs, which will increment the "lov_refcount",
so the "lov_refcount" shouldn't be checked inside because
it is always larger than 0.

Change-Id: I21423d4345190b3e02eb00734c127e35cbc9b1af
Signed-off-by: Hongchao Zhang <hongchao@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/39702
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Lai Siyao <lai.siyao@whamcloud.com>
Reviewed-by: Bobi Jam <bobijam@hotmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>