Remove library tags, they aren't needed

lib/src/codegen/module_builder.dart

Index: lib/src/codegen/module_builder.dart
diff --git a/lib/src/codegen/module_builder.dart b/lib/src/codegen/module_builder.dart
index 42d8367ae0aae0060dc53c2d74d6e12b0962b79f..48e281af1349a3f13d503b9b57738460dfae8749 100644
--- a/lib/src/codegen/module_builder.dart
+++ b/lib/src/codegen/module_builder.dart
@@ -2,8 +2,6 @@
 // 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 dev_compiler.src.codegen.module_builder;
-
 import 'package:path/path.dart' as path;
 
 import '../js/js_ast.dart' as JS;