Firstly, ask exactly what the interviewer considers to be a 'conflict'. It could mean a blazing row, or a difference of opinion, with all stops in between.
Once the definition is clear, it's much easier to answer.
'I don't have 'conflicts' as I prepare for any such occasions, and am ready to discuss amicably anything which has the remotest possibility to escalate thus. There's no point in being part of a team where working together is better than having arguments. Discussions are a completely different thing, and in my book aren't conflicts, nor should lead to them'.
Reminds me of the question - 'and when did you stop beating your wife?'
The answer of course is 'Well, sometimes I let her win the game...'