Fix bug where hasUnlinkedUnits was reporting erroneosly.
Fix bug where hasUnlinkedUnits was reporting erroneosly.

cellml/libcellml,hsorby/libcellml,hsorby/libcellml,nickerso/libcellml,nickerso/libcellml,nickerso/libcellml,hsorby/libcellml,cellml/libcellml,hsorby/libcellml,nickerso/libcellml,cellml/libcellml,cellml/libcellml