If it's not detrimental, there's no reason for it to be selected against. So, unless growing the structure of a clitoris is more-than-negligibly energy and/or nutrition demanding than growing not-clitoris, it's probably gonna stick around.

Also, if female snakes' hemiclitores are analogous to male snakes' hemipenes (that is, a base structure that develops differently for each gender), they're probably more likely to stay.