Also initialize the video sink to 'glimagesink' in case it has not been
configured from the environment, but only for the X11 application
(gtk-play). This recipe also provides a command line application for
framebuffer (gst-play) that is not affected by this change.
https://jira.digi.com/browse/DEL-2132
Signed-off-by: Javier Viguera <javier.viguera@digi.com>