VOL-3112 Group removal support by Open OLT Adapter

Change-Id: I2a21741faa2631aca5e727f73b42aa04018a2059
diff --git a/internal/pkg/core/device_handler.go b/internal/pkg/core/device_handler.go
index 2463482..9a00608 100644
--- a/internal/pkg/core/device_handler.go
+++ b/internal/pkg/core/device_handler.go
@@ -1441,8 +1441,11 @@
 				errorsList = append(errorsList, err)
 			}
 		}
-		if len(groups.ToRemove.Items) != 0 {
-			logger.Debugw(ctx, "group-delete-operation-not-supported", log.Fields{"device-id": dh.device.Id})
+		for _, group := range groups.ToRemove.Items {
+			err := dh.flowMgr.DeleteGroup(ctx, group)
+			if err != nil {
+				errorsList = append(errorsList, err)
+			}
 		}
 	}
 	if len(errorsList) > 0 {