explicitly define SolverProcess._generateRandomId() to call ActiveProcess._generateRandomId() otherwise Folder._generateRandomId() will be called and it returns 'str' not 'int' id.


git-svn-id: https://svn.erp5.org/repos/public/erp5/trunk@31282 20353a03-c40f-0410-a6d1-a30d3c3de9de