Remove an obsolete error from the spec and an obsolete command-line flag

pkg/analysis_server/lib/src/socket_server.dart

 // Copyright (c) 2014, 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 socket.server;
 
 import 'package:analysis_server/protocol/protocol.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/channel/channel.dart';
@@ skipping 70 matching lines @@
     if (analysisServerOptions.fileReadMode == 'as-is') {
       resourceProvider = PhysicalResourceProvider.INSTANCE;
     } else if (analysisServerOptions.fileReadMode == 'normalize-eol-always') {
       resourceProvider = new PhysicalResourceProvider(
           PhysicalResourceProvider.NORMALIZE_EOL_ALWAYS);
     } else {
       throw new Exception(
           'File read mode was set to the unknown mode: $analysisServerOptions.fileReadMode');
     }
 
-    Index index = null;
-    if (!analysisServerOptions.noIndex) {
-      index = createMemoryIndex();
-    }
-
     analysisServer = new AnalysisServer(
         serverChannel,
         resourceProvider,
         new PubPackageMapProvider(resourceProvider, defaultSdk),
-        index,
+        createMemoryIndex(),
         serverPlugin,
         analysisServerOptions,
         sdkManager,
         instrumentationService,
         diagnosticServer: diagnosticServer,
         fileResolverProvider: fileResolverProvider,
         packageResolverProvider: packageResolverProvider,
         useSingleContextManager: useSingleContextManager,
         rethrowExceptions: false);
     analysisServer.userDefinedPlugins = userDefinedPlugins;
   }
 }