Allow the map to have entries with a valid placement_id, but no group.
This will be useful later when the order of placement_id discovery and
group assignment may be reversed.
Signed-off-by: Ben Walker <benjamin.walker@intel.com>
Change-Id: Ia39adb3a030135940aeb9eeadf9df78056e59c0d
Reviewed-on: https://review.spdk.io/gerrit/c/spdk/spdk/+/7209
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>
Reviewed-by: Aleksey Marchuk <alexeymar@mellanox.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
4ce63b9877