ceph-disk: fix indention

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
ceph-disk: print subprocess.CalledProcessError on error

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
ceph-disk: add some more docstrings

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
ceph-disk: rename some constants to upper case variable names

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
ceph-disk: fix naming of a local variable in find_cluster_by_uuid

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
ceph-disk: rename some local variabels in list_*partitions

Signed-off-by: Danny Al-Gaaf <danny.al-gaaf@bisect.de>
Merge pull request #144 from dalgaaf/wip-da-ceph-disk

Fix some issues in ceph-dsk

Reviewed-by: Sage Weil <sage@inktank.com>