qapi: Parameter gl of DisplayType now accept an enum

v2: Rebase on top of master
v3: Fix the json format (Eric Blake)
    Fix a comparison issue (Gerd Hoffmann)

Signed-off-by: Elie Tournier <elie.tournier@collabora.com>
Message-id: 20180413135842.21325-2-tournier.elie@gmail.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
2 files changed