java: More default cleanups

nixos/modules/services/search/solr.nix

···
 
       javaPackage = mkOption {
         type = types.package;
-        default = pkgs.openjre;
+        default = pkgs.jre;
         description = ''
           Which Java derivation to use for running solr.
         '';

nixos/modules/services/web-servers/winstone.nix

···
 
       javaPackage = mkOption {
         type = types.package;
-        default = pkgs.openjre;
+        default = pkgs.jre;
         description = ''
           Which Java derivation to use for running Winstone.
         '';

pkgs/tools/graphics/zxing/default.nix

···
-{stdenv, fetchurl, openjre, jre ? openjre}:
+{ stdenv, fetchurl, jre }:
 stdenv.mkDerivation rec {
   name = "zxing-${version}";
   version = "3.1.0";