Replace QtcProcess::stopProcess() by stop() plus waitForFinished

... or nothing, if the process object is destroyed immediately.

Change-Id: I6a1e1928bc49fc20a1c0e0ee9b8f4f723276bbca
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

src/plugins/perforce/perforceplugin.cpp

@@ -1329,7 +1329,8 @@ PerforceResponse PerforcePluginPrivate::fullySynchronousProcess(const FilePath &
     QByteArray stdErr;
     const int timeOutS = (flags & LongTimeOut) ? m_settings.longTimeOutS() : m_settings.timeOutS.value();
     if (!process.readDataFromProcess(timeOutS, &stdOut, &stdErr, true)) {
-        process.stopProcess();
+        process.stop();
+        process.waitForFinished();
         response.error = true;
         response.message = msgTimeout(timeOutS);
         return response;