n#708518: sd: check that master page matches when setting parent style

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 e955433c3574cb602dedba96bc645898f97858bf)

(cherry picked from commit 5b63c12ace2aec9a659e4b9125f6aa9ff204ed09)

Conflicts:
	sd/qa/unit/import-tests.cxx

Change-Id: Ie563d5ee5c2040aeb6ca5c8bb25b195e15ea964e
Reviewed-on: https://gerrit.libreoffice.org/11195
Reviewed-by: David Tardon <dtardon@redhat.com>
Tested-by: David Tardon <dtardon@redhat.com>