before this change:
* create a note, with text
* `note` has a row with the text
* `note_edit` doesn't have any matching row
* edit the note, removing all the text
* the row in `note` has the new, empty, text
* `note_edit` has a matching row, but its `oldText` is NULL
so the original text is lost
after this change, the row in `note_edit` always keeps the previous
text
219c7fa6ec
