Leviticus 17 does contradict Deuteronomy I believe because Deuteronomy is way to vague.
Leviticus makes it clear in chapter 17 that draining the blood by a hunter or anyone that kills the animal was to do with the life of the animal. Out of respect for the animals life you took your to drain the blood. It says life three times. It was ok to eat a road kill animal and its blood because you didn't take its life. Since you didn't kill it you would only be unclean until evening.