Fix inverted logic in slog2 log handler for when to disable logging

If we are logging to the console, we should _not_ log to slog2, like
the other log backends.

Change-Id: I6d16704c0f0923f54b3dc030d374af9805c2af06
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/global/qlogging.cpp

@@ -1324,7 +1324,7 @@ static QString formatBacktraceForLogMessage(const QMessagePattern::BacktracePara
 
 static bool slog2_default_handler(QtMsgType type, const QMessageLogContext &context, const QString &message)
 {
-    if (!qt_logging_to_console())
+    if (qt_logging_to_console())
         return false;
 
     QString formattedMessage = qFormatLogMessage(type, context, message);