Fixing Issue #120 (When converting odt to pdf table of contents may have wrong page numbers)

Issue: https://github.com/dagwieers/unoconv/issues/120

I added cycle to update indexes two times.
Fixing fix for issue #120

indexes.getByIndex(i).update() must be called second time
after second call to
    document.refresh()
    indexes = document.getDocumentIndexes()
Merge pull request #127 from peterdemin/master

Third attempt to make pull request for fixing issue #120