- do not link ratpoints where it's not used

--- a/src/sage/schemes/elliptic_curves/descent_two_isogeny.pyx
+++ b/src/sage/schemes/elliptic_curves/descent_two_isogeny.pyx
@@ -1,5 +1,3 @@
-# distutils: libraries = ratpoints
-
 r"""
 Descent on elliptic curves over `\QQ` with a 2-isogeny
 """