when building invoice, use order and packing list as explanation uid, to...

when building invoice, use order and packing list as explanation uid, to collect also movements coming from the packing list

git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@25351 20353a03-c40f-0410-a6d1-a30d3c3de9de