postgresql: always create the $out/bin directory

This is needed because some PostgreSQL plugins don't have a bin
directory. If only these plugins are listed in cfg.extraPlugins buildEnv
will turn $out/bin into a symbolic link to ${pg}/bin. Lateron we try to
rm $out/bin/{pg_config,postgres,pg_ctl} which will then fail because
$out/bin will be read-only.

pkgs/servers/sql/postgresql/ext/pg_cron.nix

@@ -14,7 +14,6 @@ stdenv.mkDerivation rec {
   };
 
   installPhase = ''
-    mkdir -p $out/bin    # For buildEnv to setup proper symlinks. See #22653
     mkdir -p $out/{lib,share/extension}
 
     cp *.so      $out/lib