ParseIssuesDialog: Flush the parser

Amends 1c6e4fbd32.

Change-Id: I53bc79a6e909daf83a42ff32cc7e6f0577f3ccc1
Reviewed-by: hjk <hjk@qt.io>

src/plugins/projectexplorer/parseissuesdialog.cpp

@@ -147,6 +147,7 @@ static void parse(QFutureInterface<void> &future, const QString &output,
         if (future.isCanceled())
             return;
     }
+    parser->flush();
 }
 
 void ParseIssuesDialog::accept()