Revert "home: neovim: install the direnv plugin"

With this commmit, deoplete-go is failing on the repositories that
installs Go for some reason. I'll work on fixing this later.

This reverts commit df1558c.

modules/home/software/neovim/default.nix

@@ -77,7 +77,6 @@ in {
               "vim-bazel"
             ] ++ [ # my_plugins
               "airline-seoul256-theme"
-              "direnv-vim"
               "traces-vim"
               "vim-PreserveNoEOL"
               "vim-better-whitespace"

modules/home/software/neovim/plugins.lib.nix

@@ -188,15 +188,4 @@ in {
     };
     dependencies = [];
   };
-
-  direnv-vim = buildVimPluginFrom2Nix {
-    name = "direnv-vim-2017-12-29";
-    src = fetchFromGitHub {
-      owner = "direnv";
-      repo = "direnv.vim";
-      rev = "4d6271f0facd57a478c0d02895775dc01f577c5c";
-      sha256 = "1vfg4hrxbqc96w694cn9gzjvwkscd111fp6dqlh7wpd2z3ciw07h";
-    };
-    dependencies = [];
-  };
 }