Remove the options plugin

pkg/analysis_server/lib/src/plugin/linter_plugin.dart

-// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-library analysis_server.src.plugin.linter_plugin;
-
-import 'package:analysis_server/src/services/linter/linter.dart';
-import 'package:analyzer/plugin/options.dart';
-import 'package:plugin/plugin.dart';
-
-/// The shared linter server plugin instance.
-final LinterServerPlugin linterServerPlugin = new LinterServerPlugin();
-
-/// A plugin that defines the extension points and extensions that enhance
-/// linting in the server.
-class LinterServerPlugin implements Plugin {
-  /// The unique identifier of this plugin.
-  static const String UNIQUE_IDENTIFIER = 'linter.server';
-
-  @override
-  String get uniqueIdentifier => UNIQUE_IDENTIFIER;
-
-  @override
-  void registerExtensionPoints(RegisterExtensionPoint registerExtensionPoint) {
-    // None.
-  }
-
-  @override
-  void registerExtensions(RegisterExtension registerExtension) {
-    //
-    // Register options validators.
-    //
-    registerExtension(
-        OPTIONS_VALIDATOR_EXTENSION_POINT_ID, new LinterRuleOptionsValidator());
-  }
-}