Merge remote-tracking branch 'remotes/dgilbert-gitlab/tags/pull-virtiofs-20201026' into staging

virtiofsd pull 2020-10-26

Misono
   Set default log level to info
   Explicit build option for virtiofsd

Me
   xattr name mapping

Stefan
  Alternative chroot sandbox method

Max
  Submount mechanism

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

# gpg: Signature made Mon 26 Oct 2020 18:41:36 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-gitlab/tags/pull-virtiofs-20201026:
  tests/acceptance: Add virtiofs_submounts.py
  tests/acceptance/boot_linux: Accept SSH pubkey
  virtiofsd: Announce sub-mount points
  virtiofsd: Store every lo_inode's parent_dev
  virtiofsd: Add fuse_reply_attr_with_flags()
  virtiofsd: Add attr_flags to fuse_entry_param
  virtiofsd: Announce FUSE_ATTR_FLAGS
  linux/fuse.h: Pull in from Linux
  tools/virtiofsd: xattr name mappings: Simple 'map'
  tools/virtiofsd: xattr name mapping examples
  tools/virtiofsd: xattr name mappings: Map server xattr names
  tools/virtiofsd: xattr name mappings: Map client xattr names
  tools/virtiofsd: xattr name mappings: Add option
  virtiofsd: add container-friendly -o sandbox=chroot option
  virtiofsd: passthrough_ll: set FUSE_LOG_INFO as default log_level
  configure: add option for virtiofsd

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