Ceph install fails when LVM is in use

[Wade Fitzpatrick]

Trying to install ceph using Landscape on openstack-autopilot but I keep hitting this error:

unit-ceph-2[18220]: 2016-02-12 05:51:49 INFO unit.ceph/2.mon-relation-changed logger.go:40 ceph-disk: Error: Device /dev/sda1 is in use by a device-mapper mapping (dm-crypt?): dm-0,dm-1
unit-ceph-2[18220]: 2016-02-12 05:51:49 ERROR unit.ceph/2.juju-log server.go:268 mon:2: Unable to initialize device: /dev/sda
unit-ceph-2[18220]: 2016-02-12 05:51:49 INFO unit.ceph/2.mon-relation-changed logger.go:40 Traceback (most recent call last):
unit-ceph-2[18220]: 2016-02-12 05:51:49 INFO unit.ceph/2.mon-relation-changed logger.go:40 File "/var/lib/juju/agents/unit-ceph-2/charm/hooks/mon-relation-changed", line 432, in <module>
unit-ceph-2[18220]: 2016-02-12 05:51:49 INFO unit.ceph/2.mon-relation-changed logger.go:40 hooks.execute(sys.argv)
unit-ceph-2[18220]: 2016-02-12 05:51:49 INFO unit.ceph/2.mon-relation-changed logger.go:40 File "/var/lib/juju/agents/unit-ceph-2/charm/hooks/charmhelpers/core/hookenv.py", line 672, in execute
unit-ceph-2[18220]: 2016-02-12 05:51:49 INFO unit.ceph/2.mon-relation-changed logger.go:40 self._hooks[hook_name]()
unit-ceph-2[18220]: 2016-02-12 05:51:49 INFO unit.ceph/2.mon-relation-changed logger.go:40 File "/var/lib/juju/agents/unit-ceph-2/charm/hooks/mon-relation-changed", line 235, in mon_relation
unit-ceph-2[18220]: 2016-02-12 05:51:49 INFO unit.ceph/2.mon-relation-changed logger.go:40 reformat_osd(), config('ignore-device-errors'))
unit-ceph-2[18220]: 2016-02-12 05:51:49 INFO unit.ceph/2.mon-relation-changed logger.go:40 File "/var/lib/juju/agents/unit-ceph-2/charm/hooks/ceph.py", line 346, in osdize
unit-ceph-2[18220]: 2016-02-12 05:51:49 INFO unit.ceph/2.mon-relation-changed logger.go:40 osdize_dev(dev, osd_format, osd_journal, reformat_osd, ignore_errors)
unit-ceph-2[18220]: 2016-02-12 05:51:49 INFO unit.ceph/2.mon-relation-changed logger.go:40 File "/var/lib/juju/agents/unit-ceph-2/charm/hooks/ceph.py", line 395, in osdize_dev
unit-ceph-2[18220]: 2016-02-12 05:51:49 INFO unit.ceph/2.mon-relation-changed logger.go:40 raise e
unit-ceph-2[18220]: 2016-02-12 05:51:49 INFO unit.ceph/2.mon-relation-changed logger.go:40 subprocess.CalledProcessError: Command '['ceph-disk-prepare', '--fs-type', u'xfs', '--zap-disk', u'/dev/sda']' returned non-zero exit status 1
unit-ceph-2[18220]: 2016-02-12 05:51:49 ERROR juju.worker.uniter.operation runhook.go:107 hook "mon-relation-changed" failed: exit status 1

The osdize_dev() hook only checks partition 1 (using sgdisk, so not terribly useful on MBR labels) and does not handle the case where partition 1 is an LVM volume.

This bug is similar to #1420094