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

Two fixes for virtfs/9p from Paolo.

# gpg: Signature made Mon 30 Nov 2015 14:10:47 GMT using DSA key ID 0101DBC2
# gpg: Good signature from "Greg Kurz <gkurz@fr.ibm.com>"
# gpg:                 aka "Greg Kurz <groug@free.fr>"
# gpg:                 aka "Greg Kurz <gkurz@linux.vnet.ibm.com>"
# gpg:                 aka "Gregory Kurz (Groug) <groug@free.fr>"
# gpg:                 aka "Gregory Kurz (Cimai Technology) <gkurz@cimai.com>"
# gpg:                 aka "Gregory Kurz (Meiosys Technology) <gkurz@meiosys.com>"
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 2BD4 3B44 535E C0A7 9894  DBA2 02FC 3AEB 0101 DBC2

* remotes/gkurz/tags/for-upstream:
  virtio-9p: use QEMU thread pool
  fsdev-proxy-helper: avoid TOC/TOU race

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