Remove hard-coded disabling of debug logs

Instead, set the default level of all logs to QtWarningMsg.

The call to setFilterRules overrides the user preferences in qtlogging.ini.

Change-Id: Id5f6cd550d14ff7f45ae04c5d3110e0bafb0f072
Reviewed-by: Eike Ziller <eike.ziller@qt.io>
Reviewed-by: Kai Koehne <kai.koehne@qt.io>
Reviewed-by: hjk <hjk@qt.io>

tests/unit/unittest/unittests-main.cpp

@@ -45,8 +45,6 @@ int main(int argc, char *argv[])
 
     QCoreApplication application(argc, argv);
 
-    QLoggingCategory::setFilterRules(QStringLiteral("*.info=false\n*.debug=false\n*.warning=true"));
-
     testing::InitGoogleTest(&argc, argv);
 #ifdef WITH_BENCHMARKS
     benchmark::Initialize(&argc, argv);