erlang support: remove broken buildErlang function

The buildErlang function is broken and and leads Engineers down a wrong
path. For vanilla erlang that doesn't user rebar3, its better to simply
use `stdenv.mkDerivation` along with a set setupHook then the existing
functionality.

pkgs/development/erlang-modules/build-erlang.nix

@@ -1,68 +0,0 @@
-# This file is not used not tested at this time, build-hex.nix is the currently
-# main vehicle of bringing Erlang packages in.
-
-{ stdenv, erlang, rebar, openssl, libyaml }:
-
-{ name, version
-, buildInputs ? [], erlangDeps ? []
-, postPatch ? ""
-, meta ? {}
-, ... }@attrs:
-
-with stdenv.lib;
-
-stdenv.mkDerivation (attrs // {
-  name = "${name}-${version}";
-
-  buildInputs = buildInputs ++ [ erlang rebar openssl libyaml ];
-
-  postPatch = ''
-    rm -f rebar
-    if [ -e "src/${name}.app.src" ]; then
-      sed -i -e 's/{ *vsn *,[^}]*}/{vsn, "${version}"}/' "src/${name}.app.src"
-    fi
-    ${postPatch}
-  '';
-
-  configurePhase = let
-    getDeps = drv: [drv] ++ (map getDeps drv.erlangDeps);
-    recursiveDeps = uniqList {
-       inputList = flatten (map getDeps erlangDeps);
-    };
-  in ''
-    runHook preConfigure
-    ${concatMapStrings (dep: ''
-      header "linking erlang dependency ${dep}"
-      mkdir deps
-      ln -s "${dep}" "deps/${dep.packageName}"
-      stopNest
-    '') recursiveDeps}
-    runHook postConfigure
-  '';
-
-  buildPhase = ''
-    runHook preBuild
-    rebar compile
-    runHook postBuild
-  '';
-
-  installPhase = ''
-    runHook preInstall
-    for reldir in src ebin priv include; do
-      [ -e "$reldir" ] || continue
-      mkdir "$out"
-      cp -rt "$out" "$reldir"
-      success=1
-    done
-    runHook postInstall
-  '';
-
-  meta = {
-    inherit (erlang.meta) platforms;
-  } // meta;
-
-  passthru = {
-    packageName = name;
-    inherit erlangDeps;
-  };
-})

pkgs/development/erlang-modules/default.nix

@@ -4,7 +4,6 @@ let
   self = rec {
     hex = import ./hex-packages.nix { callPackage = self.callPackage; };
     callPackage = pkgs.lib.callPackageWith (pkgs // self // hex);
-    buildErlang = callPackage ./build-erlang.nix {};
     buildHex = callPackage ./build-hex.nix {};
   };
 in self // self.hex