ReplicatedPG: use pending_attrs in rollback

Otherwise, we won't have the correct attr_cache in
make_writeable for the clone.

Fixes: #7663
Signed-off-by: Samuel Just <sam.just@inktank.com>
ReplicatedPG: _delete_head should adjust pending_attrs

We need the old attr_cache in make_writeable for the clone,
so make the changes to pending_attrs.

Fixes: #7663
Signed-off-by: Samuel Just <sam.just@inktank.com>
ReplicatedPG: adjust pending_attrs correctly in copy_from

Otherwise, subsequent reads might not get the correct cached attrs.

Fixes: #7663
Signed-off-by: Samuel Just <sam.just@inktank.com>
Merge pull request #1417 from ceph/wip-7663

Wip 7663

Reviewed-by: Sage Weil <sage@inktank.com>