BlackBerry: Fixed running when only QML debugging is selected

The -debugNative parameter should only be passed to blackberry-deploy
when C++ debugging is enabled.

Task-number: QTCREATORBUG-11460
Change-Id: I3dba64bb57211f1c6d6b972e8afe5fa77451fb7c
Reviewed-by: Mehdi Fekari <mfekari@blackberry.com>
Reviewed-by: Fanda Vacek <fvacek@blackberry.com>
Reviewed-by: Nicolas Arnaud-Cormos <nicolas@kdab.com>
Clang: Do not use Core::MessageManager from worker thread

...since that's not thread-safe and thus leads to crashes from time to
time.

Change-Id: I907ae8b5c4d60bfc82bc97b55cc5d62d8bbeae04
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>