[REVIEW 3-6 3-6-3] fix for fdo#55885, don't insert notes to deleted cells

[Markus Mohrhard]

Hey,

[1] prevents to insert notes to deleted cells. These notes have than
negative col or row numbers so they produce a crash in the export
code.

Regards,
Markus

[1] http://cgit.freedesktop.org/libreoffice/core/commit/?id=2ec03fc221e80479557f05f53972ca864f1ff4bb