[gnome-builder] flatpak: Remove no longer present python_libprefix config opt

[Christian Hergert <chergert src gnome org>]

commit 6d5fcc9aea7cceae5fa022e114c9a33bdb3f2495
Author: vanadiae <vanadiae35 gmail com>
Date:   Fri Jul 16 18:07:59 2021 +0200

    flatpak: Remove no longer present python_libprefix config opt
    
    It was removed some time ago in bdbbfd6cec5589c743cc65da334d16e4196b7c04
    so it is no longer of any use. So remove it and avoid a meson warning
    when configuring.

 build-aux/flatpak/org.gnome.Builder.json | 1 -
 1 file changed, 1 deletion(-)
---
diff --git a/build-aux/flatpak/org.gnome.Builder.json b/build-aux/flatpak/org.gnome.Builder.json
index 3bfe7f099..e13106cff 100644
--- a/build-aux/flatpak/org.gnome.Builder.json
+++ b/build-aux/flatpak/org.gnome.Builder.json
@@ -656,7 +656,6 @@
                 "--buildtype=debugoptimized",
                 "-Dctags_path=/app/bin/ctags",
                 "-Dtcmalloc=true",
-                "-Dpython_libprefix=python3.8",
                 "-Dtracing=true",
                 "-Dhelp=true",
                 "-Dchannel=flatpak-nightly",