According to Airbus, it's because of a commercial problem with Qatar.
Airbus already had last minute troubles with Qatar claiming the aircraft does not meet the requirements and then asking for compensation (happened with a 380)
I think the bigger news was that Airbus is considering ending production of the A380 in 2018 iso of offering an NEO version. To boost sales they need a NEO version but the development of the A380NEO would cost to much (the wing needs to be redesigned for a NEO version) and will take to much time (+/- 4 years) with an uncertainty that it will fetch enough sales. So at this point they are leaning towards ending production of the A380 in 2018.
Also the only order the A380 got was a 20 piece order for a leasing company (I guess Amadeo) but since the leasing company can't find any customers for the plane they are thinking to cancel this order. This on top of Skymark which cancelled their 6-piece order this year, on top of that Air France would like to cancel the remaining 2 orders.