message: Add tf.gfile.GFile/Open rewrite rule
diff: @@ -440,6 +440,8 @@ class TFAPIChangeSpec(ast_edits.APIChangeSpec):
  "tf.io.gfile.exists",
  "tf.gfile.Glob":
  "tf.io.gfile.glob",
  + "tf.gfile.GFile":
  + "tf.io.gfile.GFile",
  "tf.gfile.IsDirectory":
  "tf.io.gfile.isdir",
  "tf.gfile.ListDirectory":
  @@ -448,6 +450,8 @@ class TFAPIChangeSpec(ast_edits.APIChangeSpec):
  "tf.io.gfile.makedirs",
  "tf.gfile.MkDir":
  "tf.io.gfile.mkdir",
  + "tf.gfile.Open":
  + "tf.io.gfile.GFile",
  "tf.gfile.Remove":
  "tf.io.gfile.remove",
  "tf.gfile.Rename":
  