RHEV: tgtd fails to load a target used for RHEV domain

Issue

• tgtd fails to load properly a target that is used for RHEV domain.
• target definition on /etc/tgt/targets.conf:

<target iqn.2011-12-14.com.redhat:fedora-ws.redhat.com>
     backing-store /dev/vg_rhev/lv_rhev_1
</target>

• Output of 'tgt-admin --show', shows only "LUN: 0", but not "LUN: 1", which is the actual lv to be loaded.
• Similar issue occur if the backing store is a partition on the system disk (e.g. /dev/sda3), where other partitions on the same local disk are used for the root LV or swap.

<target iqn.2011-12-14.com.redhat:fedora-ws.redhat.com>
     backing-store /dev/sda3
</target>