revert r32266 (set causality to Solver Decision in Target Solver documents under Solver Process), because Target Solver can be invoked without any Solver Decision, and each Target Solver portal type itself should be able to handle conflicts of target solvers.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@33942 20353a03-c40f-0410-a6d1-a30d3c3de9de