erp5_wendelin: Fix DataAnalysis_clearAndReprocessFromScratch
Remove an erroneous data_array.setStartDate(None) call in DataAnalysis_clearAndReprocessFromScratch, which is a component of the Data Analysis data_refresh_workflow.
This function was ported from a customer project configuration where Data Array has start_date and stop_date properties through a custom Property Sheet, which is not the case here.