CPatchSolver: fix yet another typo in segment-segment case

Author: lmontaut

include/hpp/fcl/contact_patch/contact_patch_solver.hxx

@@ -144,7 +144,7 @@ void ContactPatchSolver::computePatch(const ShapeType1& s1,
     const Vec2f& d = pts2[1];
 
     const FCL_REAL det =
-        (b(0) - a(0)) * (d(1) - c(1)) >= (b(1) - a(1)) * (c(0) - d(0));
+        (b(0) - a(0)) * (d(1) - c(1)) >= (b(1) - a(1)) * (d(0) - c(0));
     static constexpr FCL_REAL eps =
         Eigen::NumTraits<FCL_REAL>::dummy_precision();
     if ((std::abs(det) > eps) || ((c - d).squaredNorm() < eps) ||