Use LIO iSCSI support

The default mode for the target_helper tool is
tgtadm. To use LIO iSCSI, install the
python-rtslib package, and set
target_helper=lioadm in the cinder.conf
file.

Once configured, you can use the cinder-rtstool command to manage the volumes. This
command enables you to create, delete, and verify volumes and determine
targets and add iSCSI initiators to the system.