Merge remote-tracking branch 'remotes/kraxel/tags/pull-gtk-20150326-1' into staging

gtk: do not call gtk_widget_get_window if drawing area is not initialized

# gpg: Signature made Thu Mar 26 16:59:55 2015 GMT 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/kraxel/tags/pull-gtk-20150326-1:
  gtk: do not call gtk_widget_get_window if drawing area is not initialized

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