fixup: ERP5TypeFunctionalTestCase: support running tests on seleniumserver

See romain/erp5@f10cc273
3 jobs for for_testrunner_1
Status Job ID Name Coverage
  External
failed ERP5.UnitTest-Master

passed SlapOS.Eggs.UnitTest-Master.Python2

passed SlapOS.Eggs.UnitTest-Master.Python3