Pick up QT_LOGGING_RULES also for bootstrapped tools

Pick up logging rules set by QT_LOGGING_CONF, QT_LOGGING_RULES,
and qtlogging.ini file also for bootstrapped tools. This helps e.g.
in the case of winrtrunner, which uses categorized logging.

Change-Id: I47d392137e17a59cb57b5c0226f282b0ccf29961
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Reviewed-by: Maurice Kalinowski <maurice.kalinowski@theqtcompany.com>

src/corelib/kernel/qcoreapplication.cpp

@@ -714,9 +714,7 @@ void QCoreApplication::init()
     Q_ASSERT_X(!self, "QCoreApplication", "there should be only one application object");
     QCoreApplication::self = this;
 
-#ifndef QT_BOOTSTRAPPED
     QLoggingRegistry::instance()->init();
-#endif
 
 #ifndef QT_NO_QOBJECT
     // use the event dispatcher created by the app programmer (if any)