Claim the block devices used by iSCSI LUNs and NVMe-oF subsystems so
they can't accidentally be reused.
This will also be used by virtual block devices to allow layering of
bdevs.
Change-Id: I5384923fbf24f13f4ce720a797c5a628053d49f4
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>