Remove more libraries directives from server

pkg/analysis_server/lib/src/source/caching_pub_package_map_provider.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 source.caching_pub_package_map_provider;
-
 import 'dart:convert';
 import 'dart:core';
 import 'dart:io' as io;
 
 import 'package:analyzer/file_system/file_system.dart';
 import 'package:analyzer/source/package_map_provider.dart';
 import 'package:analyzer/source/pub_package_map_provider.dart';
 import 'package:analyzer/src/dart/sdk/sdk.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
@@ skipping 234 matching lines @@
     // TODO(danrubel) This implementation assumes that
     // two separate processes are not accessing the cache file at the same time
     io.File file = new io.File(cacheFile.path);
     if (!file.parent.existsSync()) {
       file.parent.createSync(recursive: true);
     }
     file.writeAsStringSync(content, flush: true);
     return file.lastModifiedSync().millisecondsSinceEpoch;
   }
 }