[CMake] Install missing header.

CMakeLists.txt

@@ -131,6 +131,8 @@ SET(${PROJECT_NAME}_HEADERS
   include/hpp/fcl/BV/kDOP.h
   include/hpp/fcl/narrowphase/narrowphase.h
   include/hpp/fcl/narrowphase/gjk.h
+  include/hpp/fcl/shape/convex.h
+  include/hpp/fcl/shape/details/convex.hxx
   include/hpp/fcl/shape/geometric_shape_to_BVH_model.h
   include/hpp/fcl/shape/geometric_shapes.h
   include/hpp/fcl/distance_func_matrix.h