Qnx: Fixing bb-cascades-app project template

Now it uses ProjectName:s and ProjectName:h so source code
is generated correctly.

Task-number: QTCREATORBUG-10227
Change-Id: Iecf5250e765def70d7a1d2833a02f3b2a7c3e863
Reviewed-by: David Kaspar <dkaspar@blackberry.com>
Reviewed-by: Tobias Nätterlund <tobias.naetterlund@kdab.com>
Reviewed-by: Mehdi Fekari <mfekari@blackberry.com>
Reviewed-by: Nicolas Arnaud-Cormos <nicolas@kdab.com>