update object_detection kpi type (#1702)

fluid/PaddleCV/object_detection/_ce.py

@@ -9,10 +9,10 @@ from kpi import CostKpi, DurationKpi, AccKpi
 
 train_cost_kpi = CostKpi('train_cost', 0.02, 0, actived=True)
 test_acc_kpi = AccKpi('test_acc', 0.01, 0, actived=False)
-train_speed_kpi = AccKpi('train_speed', 0.1, 0, actived=True)
+train_speed_kpi = DurationKpi('train_speed', 0.1, 0, actived=True, unit_repr="s/epoch")
 train_cost_card4_kpi = CostKpi('train_cost_card4', 0.02, 0, actived=True)
 test_acc_card4_kpi = AccKpi('test_acc_card4', 0.01, 0, actived=False)
-train_speed_card4_kpi = AccKpi('train_speed_card4', 0.1, 0, actived=True)
+train_speed_card4_kpi = DurationKpi('train_speed_card4', 0.1, 0, actived=True, unit_repr="s/epoch")
 
 tracking_kpis = [
     train_cost_kpi,