Log debug information if /liveos can't be mounted

If we can't mount /liveos, log as much information as we can
about the disks so we can try to get an idea why

Change-Id: Icb87ee4153842e90472508f0fa6594f204e84268
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1158044
Signed-off-by: Ryan Barry <rbarry@redhat.com>