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/gitlab/queryrunner.cpp

@@ -137,7 +137,8 @@ void QueryRunner::start()
 
 void QueryRunner::terminate()
 {
-    m_process.stopProcess();
+    m_process.stop();
+    m_process.waitForFinished();
 }
 
 void QueryRunner::errorTermination(const QString &msg)