Fix up QProcess::waitForFinished()

waitForFinish returns false if the process is no longer running at
the time of the call. Handle that throughout the codebase.

Change-Id: Ia7194095454e82efbd4eb88f2d55926bdd09e094
Reviewed-by: hjk <hjk@theqtcompany.com>

src/plugins/debugger/debuggersourcepathmappingwidget.cpp

@@ -415,7 +415,7 @@ static QString findQtInstallPath(const FileName &qmakePath)
         return QString();
     }
     proc.closeWriteChannel();
-    if (!proc.waitForFinished()) {
+    if (!proc.waitForFinished() && proc.state() == QProcess::Running) {
         SynchronousProcess::stopProcess(proc);
         qWarning("%s: Timeout running '%s'.", Q_FUNC_INFO, qPrintable(qmakePath.toString()));
         return QString();