Merge remote-tracking branch 'remotes/spice/tags/pull-spice-20150716-1' into staging

Merge remote-tracking branch 'remotes/spice/tags/pull-spice-20150716-1' into staging

qxl: allow to specify head limit to qxl driver

# gpg: Signature made Thu Jul 16 16:31:40 2015 BST using RSA key ID D3E87138
# gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>"
# gpg:                 aka "Gerd Hoffmann <gerd@kraxel.org>"
# gpg:                 aka "Gerd Hoffmann (private) <kraxel@gmail.com>"

* remotes/spice/tags/pull-spice-20150716-1:
  qxl: allow to specify head limit to qxl driver

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