While creating slideLayouts, a number of layouts are iterated and
master pages are created temporarily. The layout property of the slide
is set based on the mapped value.
Old value (33) seems to be typo, and is not accessible by users via UI.
The layout contains a graphical object and hence generates unexpected
image in the exported PPTX document.

Change-Id: I53af11058994a48ed6239f57f9b2b95484c76411
Reviewed-on: https://gerrit.libreoffice.org/26559Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>