ceph-volume: skip osd creation when already done

When rerunning ceph-volume lvm create on a device already prepared and
activated, ceph-volume should skip the creation.

This is a regression introduced by bb4de1a3fc

Fixes: https://tracker.ceph.com/issues/43981

Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>

src/ceph-volume/ceph_volume/devices/lvm/prepare.py

@@ -239,6 +239,9 @@ class Prepare(object):
         """
         if args is not None:
             self.args = args
+        if api.is_ceph_device(self.get_lv(self.args.data)):
+            logger.info("device {} is already used".format(self.args.data))
+            raise RuntimeError("skipping {}, it is already prepared".format(self.args.data))
         try:
             self.prepare()
         except Exception: