nbd patches for 2021-03-09

- Add Vladimir as NBD co-maintainer
- Fix reporting of holes in NBD_CMD_BLOCK_STATUS
- Improve command-line parsing accuracy of large numbers (anything going
through qemu_strtosz), including the deprecation of hex+suffix
- Improve some error reporting in the block layer

# gpg: Signature made Tue 09 Mar 2021 15:38:10 GMT
# gpg:                using RSA key 71C2CC22B1C4602927D2F3AAA7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>" [full]
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>" [full]
# gpg:                 aka "[jpeg image of size 6874]" [full]
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2021-03-09:
  block/qcow2: refactor qcow2_update_options_prepare error paths
  block/qed: bdrv_qed_do_open: deal with errp
  block/qcow2: simplify qcow2_co_invalidate_cache()
  block/qcow2: read_cache_sizes: return status value
  block/qcow2-bitmap: return status from qcow2_store_persistent_dirty_bitmaps
  block/qcow2-bitmap: improve qcow2_load_dirty_bitmaps() interface
  block/qcow2: qcow2_get_specific_info(): drop error propagation
  blockjob: return status from block_job_set_speed()
  block/mirror: drop extra error propagation in commit_active_start()
  block: drop extra error propagation for bdrv_set_backing_hd
  blockdev: fix drive_backup_prepare() missed error
  block: check return value of bdrv_open_child and drop error propagation
  utils: Deprecate hex-with-suffix sizes
  utils: Improve qemu_strtosz() to have 64 bits of precision
  utils: Enhance testsuite for do_strtosz()
  nbd: server: Report holes for raw images
  MAINTAINERS: add Vladimir as co-maintainer of NBD

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