Qnx: Fixing crash when launching BB10 application

m_futureInterface field might be 0 when reportProgress slot is called

Task-number: QTCREATORBUG-10038
Change-Id: I93931e78f3a5077bb347b184f5e61230a1955695
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>
Reviewed-by: David Kaspar <dkaspar@blackberry.com>