egl: don't terminate display
egl: don't terminate display

This is global to the display connection: all egl resources will be
released, including those from other widgets or from the application.

Fix spice/virgl display being rendered black after another widget
display is destroyed.

Signed-off-by: Marc-André Lureau <a6f2b960a4aca61381fc650a67901b2ac8e83e6d@gmail.com>
Acked-by: Pavel Grunt <fbda40b445316123f12a5a6bd7556918ea74f4bc@redhat.com>
Acked-by: Victor Toso <39b7599ff73bbf5db531748ba5250f21fa7120ff@redhat.com>

flexVDI/spice-gtk,fgouget/spice-gtk,fgouget/spice-gtk,fgouget/spice-gtk,flexVDI/spice-gtk