Block size is supposed to be optional, but it was missing the nargs
setting that makes positional parameters actually optional.
Change-Id: I8324caa956d8eaecd3ce207c9296151512b6ebea
Signed-off-by: Daniel Verkamp <daniel.verkamp@intel.com>
Reviewed-on: https://review.gerrithub.io/411942
Tested-by: SPDK Automated Test System <sys_sgsw@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Ben Walker <benjamin.walker@intel.com>