rbd: get rid of rbd_mapping::read_only

It is redundant -- rw/ro state is stored in hd_struct and managed by
the block layer.

Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
This commit is contained in:
Ilya Dryomov 2017-10-12 12:35:19 +02:00
commit 9568c93eca