Remove more libraries directives from server

pkg/analysis_server/lib/src/operation/operation.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 operation;
-
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 
 /**
  * [MergeableOperation] can decide whether other operation can be merged into
  * it, so that it should not be added as a separate operation.
  */
 abstract class MergeableOperation extends ServerOperation {
   MergeableOperation(AnalysisContext context) : super(context);
@@ skipping 71 matching lines @@
  */
 abstract class SourceSensitiveOperation extends ServerOperation {
   SourceSensitiveOperation(AnalysisContext context) : super(context);
 
   /**
    * The given [source] is about to be changed.
    * Check if this [SourceSensitiveOperation] should be discarded.
    */
   bool shouldBeDiscardedOnSourceChange(Source source);
 }