libceph: allow setting osd_req_op's flags

Signed-off-by: Yan, Zheng <zyan@redhat.com>
Reviewed-by: Alex Elder <elder@linaro.org>

diff --cc drivers/block/rbd.c
Simple merge

diff --cc fs/ceph/addr.c
Simple merge

diff --cc fs/ceph/file.c
Simple merge

diff --cc include/linux/ceph/osd_client.h
Simple merge

diff --cc net/ceph/osd_client.c
Simple merge