Since further patches will be adding new descriptors
that are related to cluster layout throughout the blobstore,
add description for existing descriptor too.
Signed-off-by: Tomasz Zawadzki <tomasz.zawadzki@intel.com>
Change-Id: I722eb633445685789d5185ed59dfc910f76b109f
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/481724
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Paul Luse <paul.e.luse@intel.com>
Reviewed-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>
3dadb79e37