Doc: Remove unrelated Qnx details

The creator-deployment-qnx contains details about deploying
BlackBerry projects using the BAR file descriptor, which doesn't
apply for all pure Qnx plarforms.

Change-Id: Iecfc2626b0de4ed016ef937b410e439c3bdc740a
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@digia.com>