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>

src/app/main.cpp

@@ -414,8 +414,6 @@ int main(int argc, char **argv)
 
     Utils::TemporaryDirectory::setMasterTemporaryDirectory(QDir::tempPath() + "/" + Core::Constants::IDE_CASED_ID + "-XXXXXX");
 
-    QLoggingCategory::setFilterRules(QLatin1String("qtc.*.debug=false\nqtc.*.info=false"));
-
 #ifdef Q_OS_MAC
     // increase the number of file that can be opened in Qt Creator.
     struct rlimit rl;