Backport of "gtk: Fix double-free when OpenGL can't be initialised" into 1.20
requested to merge tpm/gstreamer:backport-mr-2565-into-1.20-wip-hadess-gtkgstglwidget-double-free into 1.20
Backport of !2565 (merged) "gtk: Fix double-free when OpenGL can't be initialised".
Commits:
- e37c462f gtk: Fix double-free when OpenGL can't be initialised