Make app delete more stable

We still need to delete app and check how may rows affected in apps table.
 But we don't really care about other tables and rows affected there: routes, calls, logs

 We need to delete app out of loop to check for invalid numbers of rows affected:
 - zero rows means nothing happend

 Despite apps table, zero rows affected if valid case for routes, calls and logs

api/datastore/sql/sql.go

@@ -222,13 +222,13 @@ func (ds *sqlStore) UpdateApp(ctx context.Context, newapp *models.App) (*models.
 
 func (ds *sqlStore) RemoveApp(ctx context.Context, appName string) error {
 	return ds.Tx(func(tx *sqlx.Tx) error {
-		res, err := ds.db.ExecContext(ctx, ds.db.Rebind(
-			`DELETE FROM apps WHERE name = ?`), appName)
+		res, err := tx.ExecContext(ctx, tx.Rebind(`DELETE FROM apps WHERE name=?`), appName)
+		n, err := res.RowsAffected()
 		if err != nil {
 			return err
 		}
-		_, err = res.RowsAffected()
-		if err == sql.ErrNoRows {
+
+		if n == 0 {
 			return models.ErrAppsNotFound
 		}
 
@@ -239,12 +239,11 @@ func (ds *sqlStore) RemoveApp(ctx context.Context, appName string) error {
 		}
 
 		for _, stmt := range deletes {
-			_, err = ds.db.ExecContext(ctx, ds.db.Rebind(stmt), appName)
+			_, err := tx.ExecContext(ctx, tx.Rebind(stmt), appName)
 			if err != nil {
 				return err
 			}
 		}
-
 		return nil
 	})
 }