ceph::osd : add support for mon data directories

The creation of the OSD is separated in two stages, ceph-disk prepare
and ceph-disk activate. When dealing with a device this is not
necessary. But it is necessary when mon data is a directory.

The mon data directory is created if it does not exist. Although this is
not necessary for versions >= dumpling, it is for cuttlefish.

The tests are unmodified : they are run once with the /dev/sdb device
and again with the /srv/data directory.

The filestore_xattr_use_omap = true is added because cuttlefish does not
set it by default and will fail if trying to OSD::mount a directory from
a file system with limited xattr capacity such as ext4.

Note: the indentation in the tests is intentionally incorrect to not
introduce white space changes and make a clean diff.

Change-Id: Ie40eea0908b0f2e14420e2b0df2ba26e1465d23e
Signed-off-by: Loic Dachary <loic@dachary.org>
ceph::osd : indent tests

Change-Id: I5cc8f9711b02a39e7a3dc6da47ff37bd551f75e9
Signed-off-by: Loic Dachary <loic@dachary.org>
ceph::osd : add tests for osd data on an existing partition

Specifying an existing partition as osd data is supported when the
partition is properly set with the Ceph type uuid (
4fbd7e29-9d25-41b8-afd0-062c0ceff05d ). Add a test that shows it is.

Change-Id: I186647e331157a5ea8df025c0074e38a25cb238a
Signed-off-by: Loic Dachary <loic@dachary.org>