Fix sqlite test

Author: lunny

models/migrations/v184.go

@@ -20,30 +20,33 @@ func renameTaskErrorsToMessage(x *xorm.Engine) error {
 		Status int `xorm:"index"`
 	}
 
-	sess := x.NewSession()
-	defer sess.Close()
-	if err := sess.Begin(); err != nil {
-		return err
-	}
-
-	if err := sess.Sync2(new(Task)); err != nil {
-		return fmt.Errorf("error on Sync2: %v", err)
-	}
-
 	// This migration maybe rerun so that we should check if it has been run
-	exist, err := x.Dialect().IsColumnExist(x.DB(), context.Background(), "task", "message")
+	messageExist, err := x.Dialect().IsColumnExist(x.DB(), context.Background(), "task", "message")
 	if err != nil {
 		return err
 	}
-	if exist {
+
+	if messageExist {
 		errorsExist, err := x.Dialect().IsColumnExist(x.DB(), context.Background(), "task", "errors")
 		if err != nil {
 			return err
 		}
 		if !errorsExist {
 			return nil
 		}
+	}
+
+	sess := x.NewSession()
+	defer sess.Close()
+	if err := sess.Begin(); err != nil {
+		return err
+	}
+
+	if err := sess.Sync2(new(Task)); err != nil {
+		return fmt.Errorf("error on Sync2: %v", err)
+	}
 
+	if messageExist {
 		// if both errors and message exist, drop message at first
 		if err := dropTableColumns(sess, "task", "message"); err != nil {
 			return err