Merge remote-tracking branch 'remotes/vsementsov/tags/pull-nbd-2022-02-09-v2' into...

nbd: handle AioContext change correctly

v2: add my s-o-b marks to each commit

# gpg: Signature made Fri 11 Feb 2022 13:14:55 GMT
# gpg:                using RSA key 8B9C26CDB2FD147C880E86A1561F24C1F19F79FB
# gpg: Good signature from "Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 8B9C 26CD B2FD 147C 880E  86A1 561F 24C1 F19F 79FB

* remotes/vsementsov/tags/pull-nbd-2022-02-09-v2:
  iotests/281: Let NBD connection yield in iothread
  block/nbd: Move s->ioc on AioContext change
  iotests/281: Test lingering timers
  iotests.py: Add QemuStorageDaemon class
  block/nbd: Assert there are no timers when closed
  block/nbd: Delete open timer when done
  block/nbd: Delete reconnect delay timer when done

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