Revert "2048 block size for cdrom-f_mass_storage devices"

This reverts commit 7483c8f6dc3ae0ec2ff41b34bbbfc85da719ce1a.
Revert "Added cdrom option to luns"

This reverts commit 26a5c9a6fa7b9fb6416d7f83edb7dbb589b1a343.