If a block device is due to be used for a LVM PV, don't bother
creating a single partition as its not required and just adds
a layer of complexity.
This also allows partitions or bcache devices to be consumed
as block devices for ceph OSD's.
Change-Id: I6fac0c781e269c229fb4781dd6683a7236d8e960
Helper functions for the ceph charms. This library has shared functionality that is used in the ceph-mon, ceph-osd and ceph
charms. Anything that needs to be shared across the ceph charms should live here.