obsstore: keep self._data updated with _addmarkers
This makes sure obsstore._data is still correct with added markers.
The '_data' propertycache was added in
17ce57b7873f.
# See http://EditorConfig.org for the specification
root = true
[*.py]
indent_size = 4
indent_style = space
trim_trailing_whitespace = true
[*.{c,h}]
indent_size = 8
indent_style = tab
trim_trailing_whitespace = true