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

Block layer patches

- Fix I/O errors because of incorrectly detected max_iov
- Fix not white-listed copy-before-write
- qemu-storage-daemon: Only display FUSE help when FUSE is built-in
- iotests: update environment and linting configuration

# gpg: Signature made Wed 06 Oct 2021 03:58:10 AM PDT
# gpg:                using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg:                issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]

* remotes/kwolf/tags/for-upstream:
  iotests: Update for pylint 2.11.1
  iotests/migrate-bitmaps-test: delint
  iotests/mirror-top-perms: Adjust imports
  iotests/linters: check mypy files all at once
  iotests: add 'qemu' package location to PYTHONPATH in testenv
  block: introduce max_hw_iov for use in scsi-generic
  iotests/image-fleecing: declare requirement of copy-before-write
  block: bdrv_insert_node(): don't use bdrv_open()
  block: bdrv_insert_node(): doc and style
  block: bdrv_insert_node(): fix and improve error handling
  block: implement bdrv_new_open_driver_opts()
  qemu-storage-daemon: Only display FUSE help when FUSE is built-in
  include/block.h: remove outdated comment

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>