Remove more libraries directives from server

pkg/analysis_server/lib/src/domains/analysis/occurrences_dart.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 domains.analysis.occurrences_dart;
-
 import 'package:analysis_server/plugin/analysis/occurrences/occurrences_core.dart';
 import 'package:analysis_server/src/protocol_server.dart' as protocol;
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/element.dart';
 import 'package:analyzer/src/dart/element/member.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 
@@ skipping 59 matching lines @@
     }
     if (element is PropertyAccessorElement) {
       element = (element as PropertyAccessorElement).variable;
     }
     if (element is Member) {
       element = (element as Member).baseElement;
     }
     return element;
   }
 }