There don't seem any publicly available binaries for openh264 for
openSUSE 15.5 anymore. Removing gstreamer and openh264 headers will
allow us to build binaries, at the cost of not being able to build the
gstreamer plugin anymore.
Pick-to: 6.8 dev 6.9 6.9.0
Change-Id: Ief1e9eb3963e98a1e2b076c3a3bfd8bdeec21e3c
Reviewed-by: Liang Qi <liang.qi@qt.io>
Reviewed-by: Jøger Hansegård <joger.hansegard@qt.io>
336fc07c80