Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2017-11-28' into staging

Merge remote-tracking branch 'remotes/ericb/tags/pull-nbd-2017-11-28' into staging

nbd patches for 2017-11-28

Eric Blake - 0/2 fix two NBD server CVEs

# gpg: Signature made Tue 28 Nov 2017 12:58:29 GMT
# gpg:                using RSA key 0xA7A16B4A2527436A
# gpg: Good signature from "Eric Blake <eblake@redhat.com>"
# gpg:                 aka "Eric Blake (Free Software Programmer) <ebb9@byu.net>"
# gpg:                 aka "[jpeg image of size 6874]"
# Primary key fingerprint: 71C2 CC22 B1C4 6029 27D2  F3AA A7A1 6B4A 2527 436A

* remotes/ericb/tags/pull-nbd-2017-11-28:
  nbd/server: CVE-2017-15118 Stack smash on large export name
  nbd/server: CVE-2017-15119 Reject options larger than 32M

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