ronn: rename env used for bundlerEnv to rubyEnv

`env` is now only allowed to be an attribute set in `stdenv.mkDerivation`

pkgs/by-name/ro/ronn/package.nix

@@ -7,15 +7,15 @@
   groff,
   callPackage,
 }:
-
-stdenv.mkDerivation rec {
-  pname = "ronn";
-  version = env.gems.ronn-ng.version;
-
-  env = bundlerEnv {
+let
+  rubyEnv = bundlerEnv {
     name = "ronn-gems";
     gemdir = ./.;
   };
+in
+stdenv.mkDerivation {
+  pname = "ronn";
+  version = rubyEnv.gems.ronn-ng.version;
 
   dontUnpack = true;
 
@@ -27,7 +27,7 @@ stdenv.mkDerivation rec {
     runHook preInstall
 
     mkdir -p $out/bin
-    makeWrapper ${env}/bin/ronn $out/bin/ronn \
+    makeWrapper ${rubyEnv}/bin/ronn $out/bin/ronn \
       --set PATH ${groff}/bin
 
     runHook postInstall
@@ -46,6 +46,6 @@ stdenv.mkDerivation rec {
       zimbatm
       nicknovitski
     ];
-    platforms = env.ruby.meta.platforms;
+    platforms = rubyEnv.ruby.meta.platforms;
   };
 }