[fractal/fractal-next] flatpak: drop uneeded env variables

[Julian Sparber <jsparber src gnome org>]

commit 4d93119299b8768e80c70a68771a7f4f1427115f
Author: Veli Tasali <veli tasali gmail com>
Date:   Thu May 6 19:30:50 2021 +0300

    flatpak: drop uneeded env variables
    
    
https://gitlab.gnome.org/bilelmoussaoui/gtk-rust-template/-/commit/67468b7ef2cf6a997cf9f5534e5fac301a0e1a26

 build-aux/org.gnome.FractalNext.Devel.json | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
---
diff --git a/build-aux/org.gnome.FractalNext.Devel.json b/build-aux/org.gnome.FractalNext.Devel.json
index 29730038..060d14f9 100644
--- a/build-aux/org.gnome.FractalNext.Devel.json
+++ b/build-aux/org.gnome.FractalNext.Devel.json
@@ -25,9 +25,7 @@
             "--share=network"
         ],
         "env" : {
-            "CARGO_HOME" : "/run/build/fractal/cargo",
-            "RUST_BACKTRACE": "1",
-            "RUSTFLAGS": "-L=/app/lib"
+            "RUST_BACKTRACE": "1"
         }
     },
     "modules": [