In ODF import it happened that the parent style of "outline2" etc.
was always set to the "outline1" style of the first master page in
the document, but it should be the "outline1" style of the same master
page as the "outline2".

(regression from e955433c)

Change-Id: Ie563d5ee5c2040aeb6ca5c8bb25b195e15ea964e