Fix gcc warnings

include/hpp/fcl/BV/OBB.h

include/hpp/fcl/BV/OBBRSS.h

include/hpp/fcl/BV/RSS.h

include/hpp/fcl/BV/kIOS.h

include/hpp/fcl/BVH/BVH_internal.h

include/hpp/fcl/broadphase/broadphase.h

include/hpp/fcl/ccd/motion.h

include/hpp/fcl/ccd/motion_base.h

include/hpp/fcl/narrowphase/narrowphase.h

include/hpp/fcl/shape/geometric_shapes.h

include/hpp/fcl/traversal/traversal_node_base.h

include/hpp/fcl/traversal/traversal_node_bvh_shape.h

src/BV/OBB.cpp

src/BV/kIOS.cpp

src/ccd/interpolation/interpolation_linear.cpp

src/collision.cpp

src/distance_func_matrix.cpp

src/narrowphase/narrowphase.cpp