fixed var name for ansible vault editing existing data

v2/ansible/parsing/vault/__init__.py

@@ -203,7 +203,7 @@ class VaultEditor(object):
         _, tmp_path = tempfile.mkstemp()
 
         if existing_data:
-            self.write_data(data, tmp_path)
+            self.write_data(existing_data, tmp_path)
 
         # drop the user into an editor on the tmp file
         call(self._editor_shell_command(tmp_path))