Without this we may see the following error in cinder-backup when using
the LVM backend:
Could not login to any iSCSI portal
Enabling the iscsid container on hosts in the cinder-backup group fixes
this.
Closes-Bug: #1838624
Change-Id: If373c002b0744ce9dbdffed50a02bab55dd0acb9
Co-Authored-By: dmitry-a-grachev <dmitry.a.grachev@gmail.com>