Merge remote-tracking branch 'kraxel/tags/pull-ui-20170519-1' into staging

ui: egl-headless requires dmabuf support

# gpg: Signature made Fri 19 May 2017 09:46:40 AM BST
# gpg:                using RSA key 0x4CB6D8EED3E87138
# 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>"
# Primary key fingerprint: A032 8CFF B93A 17A7 9901  FE7D 4CB6 D8EE D3E8 7138

* kraxel/tags/pull-ui-20170519-1:
  ui: egl-headless requires dmabuf support

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>