Fix workflow to cater for URL in custom_actions
Fix workflow to cater for URL in custom_actions

the URL in the workflow definition is ignored, if the action
was not defined as a custom_action.

This prepares for the day when WorkflowAction classes are abolished,
and fixes #1194

rockfruit/bika.lims,DeBortoliWines/Bika-LIMS,anneline/Bika-LIMS,anneline/Bika-LIMS,veroc/Bika-LIMS,DeBortoliWines/Bika-LIMS,rockfruit/bika.lims,veroc/Bika-LIMS,labsanmartin/Bika-LIMS,veroc/Bika-LIMS,DeBortoliWines/Bika-LIMS,anneline/Bika-LIMS,labsanmartin/Bika-LIMS,labsanmartin/Bika-LIMS