rbd/tests: add special "read 0 bytes" case
rbd/tests: add special "read 0 bytes" case

Signed-off-by: Niels de Vos <7bda0c0ee7f47171cc808e9e60292cbc5d8140dd@redhat.com>

ceph/go-ceph,ceph/go-ceph,ceph/go-ceph