When we export the customshape as polypolygon, we need to
take into account, that the polypolygon of the shape already
has flipped coordinates, but coordinates has to be relative
to the rotated bounding rectangle.

Change-Id: I4f3b015e439d3d6041adc67eddd460f5bd4dfca1
Reviewed-on: https://gerrit.libreoffice.org/21905Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Andras Timar <andras.timar@collabora.com>