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

This fixes a bad errno returned to the guest and a trivial coding style nit.

# gpg: Signature made Mon 06 Nov 2017 18:09:24 GMT
# gpg:                using RSA key 0x71D4D5E5822F73D6
# gpg: Good signature from "Greg Kurz <groug@kaod.org>"
# gpg:                 aka "Gregory Kurz <gregory.kurz@free.fr>"
# gpg:                 aka "[jpeg image of size 3330]"
# Primary key fingerprint: B482 8BAF 9431 40CE F2A3  4910 71D4 D5E5 822F 73D6

* remotes/gkurz/tags/for-upstream:
  9pfs: fix v9fs_mark_fids_unreclaim() return value
  9pfs: drop one user of struct V9fsFidState

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