EMF+: Stroke size is always supposed to be absolute.

Change-Id: I7221311e5dee6384dc2d1c071bf6f1c61811895a
Reviewed-on: https://gerrit.libreoffice.org/6827
Reviewed-by: Andras Timar <andras.timar@collabora.com>
Tested-by: Andras Timar <andras.timar@collabora.com>