nix-on-droid: remove fallback for default nix < 2.4

Nixpkgs 22.11 has the default nix package with version 2.11.0.

nix-on-droid/default.nix

@@ -1,6 +1,6 @@
-# Copyright (c) 2019-2020, see AUTHORS. Licensed under MIT License, see LICENSE.
+# Copyright (c) 2019-2022, see AUTHORS. Licensed under MIT License, see LICENSE.
 
-{ bash, coreutils, lib, nix, nix_2_4, runCommand }:
+{ bash, coreutils, lib, nix, runCommand }:
 
 runCommand
   "nix-on-droid"
@@ -14,6 +14,5 @@ runCommand
     substituteInPlace $out/bin/nix-on-droid \
       --subst-var-by bash "${bash}" \
       --subst-var-by coreutils "${coreutils}" \
-      --subst-var-by nix "${nix}" \
-      --subst-var-by nixge24 "${if lib.versionAtLeast nix.version "2.4pre" then nix else nix_2_4}"
+      --subst-var-by nix "${nix}"
   ''

nix-on-droid/nix-on-droid.sh

@@ -28,15 +28,13 @@ function nixActivationPackage() {
     local extraArgs=("${@:2}"
                      --extra-experimental-features nix-command
                      "${PASSTHROUGH_OPTS[@]}")
-    local nix=nix
     if [[ -n "${FLAKE_CONFIG_URI}" ]]; then
-        nix=@nixge24@/bin/nix
         extraArgs+=(--impure "${FLAKE_CONFIG_URI}.activationPackage")
     else
         extraArgs+=(--file "<nix-on-droid/modules>" activationPackage)
     fi
 
-    $nix "${command}" "${extraArgs[@]}"
+    nix "${command}" "${extraArgs[@]}"
 }