Merge remote-tracking branch 'stefanha/block-next' into staging

# By Stefan Hajnoczi
# Via Stefan Hajnoczi
* stefanha/block-next:
  aio: drop io_flush argument
  tests: drop event_active_cb()
  thread-pool: drop thread_pool_active()
  dataplane/virtio-blk: drop flush_true() and flush_io()
  block/ssh: drop return_true()
  block/sheepdog: drop have_co_req() and aio_flush_request()
  block/rbd: drop qemu_rbd_aio_flush_cb()
  block/nbd: drop nbd_have_request()
  block/linux-aio: drop qemu_laio_completion_cb()
  block/iscsi: drop iscsi_process_flush()
  block/gluster: drop qemu_gluster_aio_flush_cb()
  block/curl: drop curl_aio_flush()
  aio: stop using .io_flush()
  tests: adjust test-thread-pool to new aio_poll() semantics
  tests: adjust test-aio to new aio_poll() semantics
  dataplane/virtio-blk: check exit conditions before aio_poll()
  block: stop relying on io_flush() in bdrv_drain_all()
  block: ensure bdrv_drain_all() works during bdrv_delete()

Message-id: 1376921877-9576-1-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <anthony@codemonkey.ws>