Comment 2 for bug 1718055

Note this is fixed in upstream debian by commit:

commit 3cb744c9cf39f0dc178370ef6235a1b30f8c7d06
Author: Ben Hutchings <email address hidden>
Date: Tue Dec 8 02:53:23 2015 +0000

    hook-functions: Rewrite block device sysfs lookup to be generic

That commit is a larger change that reworks the entire way initramfs parses /dev/* names into underlying sys block device names, and is more change that is required to get trusty initramfs-tools working for this bug.