Revert "add warning for deprecated .analysis_options file name"

pkg/analyzer/lib/src/task/options.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 analyzer.src.task.options;
 
 import 'dart:collection';
 
 import 'package:analyzer/analyzer.dart';
 import 'package:analyzer/plugin/options.dart';
@@ skipping 220 matching lines @@
   Source get source => target.source;
 
   @override
   void internalPerform() {
     String content = getRequiredInput(CONTENT_INPUT_NAME);
 
     List<AnalysisError> errors = <AnalysisError>[];
     Source initialSource = source;
     SourceSpan initialIncludeSpan;
 
-    // Suggest user rename deprecated .analysis_options file
-    String fullName = target?.source?.fullName;
-    if (fullName != null &&
-        fullName.endsWith(AnalysisEngine.ANALYSIS_OPTIONS_FILE)) {
-      errors.add(new AnalysisError(
-          source,
-          0, // offset
-          1, // length
-          AnalysisOptionsWarningCode.DEPRECATED_ANALYSIS_OPTIONS_FILE_NAME,
-          [fullName]));
-    }
-
     // Validate the specified options and any included option files
     void validate(Source source, Map<String, YamlNode> options) {
       List<AnalysisError> validationErrors =
           new OptionsFileValidator(source).validate(options);
       if (initialIncludeSpan != null && validationErrors.isNotEmpty) {
         for (AnalysisError error in validationErrors) {
           var args = [
             source.fullName,
             error.offset.toString(),
             (error.offset + error.length - 1).toString(),
@@ skipping 335 matching lines @@
         }
       });
     } else if (config is Map) {
       options.strongMode = true;
       config.forEach((k, v) => _applyStrongModeOption(options, k, v));
     } else {
       options.strongMode = config is bool ? config : false;
     }
   }
 }