Merge remote-tracking branch 'remotes/berrange/tags/qio-next-pull-request' into staging

# gpg: Signature made Thu 15 Feb 2018 17:50:22 GMT
# gpg:                using RSA key BE86EBB415104FDF
# gpg: Good signature from "Daniel P. Berrange <dan@berrange.com>"
# gpg:                 aka "Daniel P. Berrange <berrange@redhat.com>"
# Primary key fingerprint: DAF3 A6FD B26B 6291 2D0E  8E3F BE86 EBB4 1510 4FDF

* remotes/berrange/tags/qio-next-pull-request:
  allow to build with older sed
  io/channel-command: Do not kill the child process after closing the pipe
  io: Add /dev/fdset/ support to QIOChannelFile
  io: Don't call close multiple times in QIOChannelFile
  io: Fix QIOChannelFile when creating and opening read-write
  io/channel-websock: handle continuous reads without any data
  io: fix QIONetListener memory leak

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