Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging

Merge remote-tracking branch 'remotes/bonzini/tags/for-upstream' into staging

* nbd and qemu-nbd fixes (Eric, Max)
* nbd refactoring (Vladimir)
* vhost-user-scsi, take N+1 (Felipe)
* replace memory_region_set_fd with memory_region_init_ram_from_fd (Marc-André)
* docs/ movement (Paolo)
* megasas TOCTOU fixes (Paolo)
* make async_safe_run_on_cpu work on kvm/hax accelerators (Paolo)
* Build system and poison.h improvements (Thomas)
* -accel thread=xxx fix (Thomas)
* move files to accel/ (Yang Zhong)

# gpg: Signature made Thu 15 Jun 2017 10:51:55 BST
# gpg:                using RSA key 0xBFFBD25F78C7AE83
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>"
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>"
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4  E2F7 7E15 100C CD36 69B1
#      Subkey fingerprint: F133 3857 4B66 2389 866C  7682 BFFB D25F 78C7 AE83

* remotes/bonzini/tags/for-upstream: (41 commits)
  vhost-user-scsi: Introduce a vhost-user-scsi sample application
  vhost-user-scsi: Introduce vhost-user-scsi host device
  qemu-doc: include version number
  docs: create interop/ subdirectory
  include/exec/poison: Mark some CONFIG defines as poisoned, too
  include/exec/poison: Add missing TARGET defines
  nbd/server: refactor nbd_trip
  nbd/server: rename rc to ret
  nbd/server: get rid of fail: return rc
  nbd/server: nbd_negotiate: fix error path
  nbd/server: remove NBDClientNewData
  nbd/server: refactor nbd_co_receive_request
  nbd/server: get rid of EAGAIN dead code
  nbd/server: refactor nbd_co_send_reply
  nbd/server: get rid of ssize_t
  nbd/server: get rid of nbd_negotiate_read and friends
  nbd: make nbd_drop public
  nbd: rename read_sync and friends
  accel: move kvm related accelerator files into accel/
  tcg: move tcg backend files into accel/tcg/
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>