Fix 'Unused local variable' hints in analyzer and analysis_server.

pkg/analysis_server/lib/src/edit/edit_domain.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 edit.domain;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/collections.dart';
@@ skipping 276 matching lines @@
       });
     });
   }
 
   /**
    * Initializes this context to perform a refactoring with the specified
    * parameters. The existing [Refactoring] is reused or created as needed.
    */
   Future<RefactoringStatus> _init(RefactoringKind kind, String file, int offset,
       int length) {
-    List<RefactoringProblem> problems = <RefactoringProblem>[];
     // check if we can continue with the existing Refactoring instance
     if (this.kind == kind &&
         this.file == file &&
         this.offset == offset &&
         this.length == length) {
       return new Future.value(initStatus);
     }
     _reset();
     this.kind = kind;
     this.file = file;
@@ skipping 183 matching lines @@
     }
     if (refactoring is RenameRefactoring) {
       RenameRefactoring renameRefactoring = refactoring;
       RenameOptions renameOptions = params.options;
       renameRefactoring.newName = renameOptions.newName;
       return renameRefactoring.checkNewName();
     }
     return new RefactoringStatus();
   }
 }