Comment 7 for bug 1246708

This bug has been fixed in Juno and backported to stable/Icehouse

commit 1613cd99345e51e314bf011f47654ed730138f64
Author: Roman Podoliaka <email address hidden>
Date: Fri Aug 22 20:01:33 2014 +0300

    Fix instance boot when Ceph is used for ephemeral storage

    is_block_dev attribute was mistakenly set to True for RBD images
    (we don't actually map RBD images to block devices in the *host*
    system, but only in *guests*, so as far as the host system is
    concerned an RBD image must not be treated like a system block
    device). This led to a situation when mkfs was called for a non
    existing file and failed when trying to create an ephemeral fs.

    Closes-Bug: #1362221

    Change-Id: I54c0d117a53bb61f278b2e137bd29a595548f5a1
    (cherry picked from commit e9eb1d69bf75c22b0ad4b50e4892a5644c78cf68)