librbd: use order-agnostic default stripe parameters

This way the default striping style of splitting into
object-sized chunks still works with non-default orders
specified.

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
rbd: remove accidental repeated option

--stripe-count is already parsed above this

Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
rbd: respect rbd_default_* parameters

Treat rbd_default_{format,order,stripe_unit,stripe_count} as defaults for
the usual arguments for specifying those properties.

librbd::create() is affected by rbd_default_format, so we need to
explicitly override it if --image-format is set. The rest of the
parameters are passed explicitly when they are used, so their rbd_default
equivalents don't matter.

Fixes: #8821
Signed-off-by: Josh Durgin <josh.durgin@inktank.com>
Merge pull request #2112 from ceph/wip-rbd-defaults

respect rbd_default_* parameters in /usr/bin/rbd

Reviewed-by: Sage Weil <sage@redhat.com>