Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20201218a' into staging

Monitor, virtiofsd and migration pull

HMP cleanups
Migration fixes
  Note the change in behaviour of not allowing a postmigrate migrtion
  rather than crashing

Virtiofsd cleanups and fixes
  --thread-pool-size=0 for no thread pool (faster for some workloads)

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

# gpg: Signature made Fri 18 Dec 2020 10:39:37 GMT
# gpg:                using RSA key 45F5C71B4A0CB7FB977A9FA90516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>" [full]
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert/tags/pull-migration-20201218a:
  migration: Don't allow migration if vm is in POSTMIGRATE
  savevm: Delete snapshots just created in case of error
  savevm: Remove dead code in save_snapshot()
  docs/devel/migration: Improve debugging section a bit
  virtiofsd: Remove useless code about send_notify_iov
  virtiofsd: update FUSE_FORGET comment on "lo_inode.nlookup"
  virtiofsd: Check file type in lo_flush()
  virtiofsd: Disable posix_lock hash table if remote locks are not enabled
  virtiofsd: Set up posix_lock hash table for root inode
  virtiofsd: make the debug log timestamp on stderr more human-readable
  virtiofsd: Use --thread-pool-size=0 to mean no thread pool
  hmp-commands.hx: List abbreviation after command for cont, quit, print
  monitor:Don't use '#' flag of printf format ('%#') in format strings
  monitor:braces {} are necessary for all arms of this statement
  monitor:open brace '{' following struct go on the same line

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