Multi-statement queries should always return an array.

- at the moment the return type is different depending on how many
  queries were run.
- See: mysqljs/mysql#1367

Author: JamesBarwell

src/connection/DbConnection.js

@@ -112,6 +112,9 @@ module.exports = (
                             return reject(err);
                         }
                         releaseConnection(connection);
+                        if (!Array.isArray(rows)) {
+                            rows = [rows];
+                        }
                         return resolve(rows);
                     });
                 })