Merge remote-tracking branch 'remotes/dgilbert-gitlab/tags/pull-virtiofs-20200221...

Merge remote-tracking branch 'remotes/dgilbert-gitlab/tags/pull-virtiofs-20200221' into staging

virtiofs pull 20200221

Mostly minor cleanups.
Miroslav's fixes a make install corner case.
Philippe's set includes an error corner case fix.

# gpg: Signature made Fri 21 Feb 2020 13:21:39 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-20200221:
  docs: Fix virtiofsd.1 location
  virtiofsd: Remove fuse.h and struct fuse_module
  tools/virtiofsd/fuse_lowlevel: Fix fuse_out_header::error value
  tools/virtiofsd/passthrough_ll: Remove unneeded variable assignment
  tools/virtiofsd/passthrough_ll: Remove unneeded variable assignment
  virtiofsd: Help message fix for 'seconds'

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