Fix zonal stats algorithm execution

Author: nyalldawson

python/plugins/processing/algs/qgis/ZonalStatistics.py

@@ -125,7 +125,7 @@ def processAlgorithm(self, context, feedback):
                                 self.rasterLayer,
                                 self.columnPrefix,
                                 self.bandNumber,
-                                self.selectedStats)
+                                QgsZonalStatistics.Statistics(self.selectedStats))
         zs.calculateStatistics(feedback)
         return True