packaging: setup: iscsi: add multiple lun per target support

Add support for multiple lun on the same target.
It allows to choose the lun to be used when more than one
is available on the target.

Change-Id: I0b00cc09754a8b95bc1497e0f769ae2a9c64f1b5
Bug-Url: https://bugzilla.redhat.com/1125315
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>