QNX: Use correct command for running the SDK installer

Depending on NDK version, the application used for the
SDK installer is different.

Without this, the installation of NDK's is not possible
from within Qt Creator.

Change-Id: I71ba67ccb05d30bcef5b63e7e397e545c5a89e3e
Reviewed-by: Nicolas Arnaud-Cormos <nicolas@kdab.com>
Reviewed-by: David Kaspar <dkaspar@blackberry.com>
Reviewed-by: Mehdi Fekari <mfekari@blackberry.com>
Reviewed-by: Rafael Roquetto <rafael.roquetto@kdab.com>