qmlplugindump: fix bug in reading command line

Task-number: QTBUG-58264
Change-Id: I317fb18d9ceb8738f2f132b8703dc1af3b17d35b
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

tools/qmlplugindump/main.cpp

@@ -999,7 +999,7 @@ int main(int argc, char *argv[])
     // Check which kind of application should be instantiated.
     bool useQApplication = false;
     for (int i = 0; i < argc; ++i) {
-        QString arg = QLatin1String(argv[1]);
+        QString arg = QLatin1String(argv[i]);
         if (arg == QLatin1String("--qapp") || arg == QLatin1String("-qapp"))
             useQApplication = true;
     }