recipes/custom.py: Also remove library include dirs
recipes/custom.py: Also remove library include dirs

Sometimes we install things into lib/gstreamer-1.0/include, so remove
those too when disabling a library.

Part-of: <https://gitlab.freedesktop.org/gstreamer/cerbero/-/merge_requests/497>

nirbheek/cerbero,GStreamer/cerbero,nirbheek/cerbero,GStreamer/cerbero,GStreamer/cerbero,nirbheek/cerbero,GStreamer/cerbero,GStreamer/cerbero,nirbheek/cerbero