When is a brake hard line 'kinked'

I would say that the line in the picture wasn't quite kinked.. However Its hard to tell via a picture if fluid flow would be restricted or not. The only way you'd be able to tell properly is if the brakes were working evenly on that axle. If I were you I'd just run another length, but If you're wanting/willing to leave it like that, you'll at least have to have the brakes checked on a rolling road to make sure the brake balance is ok.