IO: Fix FileSystemEntity.get:parent comment.

sdk/lib/io/file_system_entity.dart

Index: sdk/lib/io/file_system_entity.dart
diff --git a/sdk/lib/io/file_system_entity.dart b/sdk/lib/io/file_system_entity.dart
index 41bee01181a3c5afc143bb17973bf93fc91f7b2c..2a4a1f5140fd857e4b37bd0b932e4dc7776cc106 100644
--- a/sdk/lib/io/file_system_entity.dart
+++ b/sdk/lib/io/file_system_entity.dart
@@ -653,8 +653,7 @@ abstract class FileSystemEntity {
   }
 
   /**
-   * The directory containing [this].  If [this] is a root
-   * directory, returns [this].
+   * The directory containing [this].
    */
   Directory get parent => new Directory(parentOf(path));