Camera lookat needs to be calculated after camera position is set.

Change-Id: I0a858e47074573037e590211d9ae383c5b8171ff
Reviewed-by: Tomi Korpipää <tomi.korpipaa@theqtcompany.com>
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@theqtcompany.com>