global-platform-pro: stop overwriting maven

pkgs/development/tools/global-platform-pro/default.nix

···
 { lib, stdenv, fetchFromGitHub, jdk8, maven, makeWrapper, jre8_headless, pcsclite, proot, zlib }:
 
 let
-  mavenJdk8 = maven.override {
-    jdk = jdk8;
-  };
-
   defineMvnWrapper = ''
     mvn()
     {
···
     }
   '';
 in
-mavenJdk8.buildMavenPackage rec {
+maven.buildMavenPackage rec {
   pname = "global-platform-pro";
   version = "20.01.23";
   GPPRO_VERSION = "v20.01.23-0-g5ad373b"; # git describe --tags --always --long --dirty
···
     sha256 = "sha256-z38I61JR4oiAkImkbwcvXoK5QsdoR986dDrOzhHsCeY=";
   };
 
+  mvnJdk = jdk8;
   mvnHash = "sha256-es8M7gV2z1V9VpWOxanJwQyiemabiUw3n4heJB8Q75A=";
 
   nativeBuildInputs = [ jdk8 makeWrapper ];