Modify generateNewLengthId to call generateNewLengthIdList.
generateNewLengthIdList contains code which belonged to generateNewLengthId with more comments and safe fallbacks in case of problem (which means that this function now raises when its requirements are not met).


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@13736 20353a03-c40f-0410-a6d1-a30d3c3de9de