[gnome-builder] flatpak: remove dead code

[Christian Hergert <chergert src gnome org>]

commit 956c3bd04e89fee98484f59ab0d592d9b60435bb
Author: Christian Hergert <chergert redhat com>
Date:   Mon Nov 29 15:10:00 2021 -0800

    flatpak: remove dead code
    
    This didn't get used

 src/plugins/flatpak/gbp-flatpak-aux.c | 1 -
 1 file changed, 1 deletion(-)
---
diff --git a/src/plugins/flatpak/gbp-flatpak-aux.c b/src/plugins/flatpak/gbp-flatpak-aux.c
index a1c125064..92a2f9856 100644
--- a/src/plugins/flatpak/gbp-flatpak-aux.c
+++ b/src/plugins/flatpak/gbp-flatpak-aux.c
@@ -26,7 +26,6 @@
 
 #define SYSTEM_FONTS_DIR       "/usr/share/fonts"
 #define SYSTEM_LOCAL_FONTS_DIR "/usr/local/share/fonts"
-#define HOST_PREFIX            "/var/run/host"
 
 /* dirs are reversed from flatpak because we will always have
  * /var/cache/fontconfig inside of flatpak. We really need another