Added defaultLookup node to lookup.productIncomeType

git-svn-id: svn://svn.openvpms.org/openvpms/archetypes/trunk@6241 9e4fa352-aafb-0310-9071-df624684024b
Changes for OVPMS-1527 "Generate Orders generates multiple order items if a product and supplier has 2 or more preferred relationships"
to ensure that if there are multiple relationships and one of them is preferred and a preferred supplier is set on the stock location, the preferred supplier relationship is selected

git-svn-id: svn://svn.openvpms.org/openvpms/archetypes/trunk@6247 9e4fa352-aafb-0310-9071-df624684024b