Merge remote-tracking branch 'remotes/mdroth/tags/qga-pull-2015-11-04-tag' into staging

qemu-ga patch queue

* fix file handle cleanup on w32
* use non-blocking mode for file handles on w32 to avoid
  hangs on guest-file-read/guest-file-write to pipes

# gpg: Signature made Wed 04 Nov 2015 19:36:16 GMT using RSA key ID F108B584
# gpg: Good signature from "Michael Roth <flukshun@gmail.com>"
# gpg:                 aka "Michael Roth <mdroth@utexas.edu>"
# gpg:                 aka "Michael Roth <mdroth@linux.vnet.ibm.com>"

* remotes/mdroth/tags/qga-pull-2015-11-04-tag:
  qga: set file descriptor in qmp_guest_file_open non-blocking on Win32
  qga: fixed CloseHandle in qmp_guest_file_open
  qga: drop hand-made guest_file_toggle_flags helper

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