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

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

# By MORITA Kazutaka (5) and others
# Via Stefan Hajnoczi
* stefanha/block:
  block: for HMP commit() operations on 'all', skip non-COW drives
  sheepdog: add support for connecting to unix domain socket
  sheepdog: use inet_connect to simplify connect code
  sheepdog: accept URIs
  move socket_set_nodelay to osdep.c
  slirp/tcp_subr.c: fix coding style in tcp_connect
  dataplane: remove EventPoll in favor of AioContext
  virtio-blk: fix unplug + virsh reboot
  ide/macio: Fix macio DMA initialisation.