ocfs2: Use nd_set_link().

ocfs2 was hand-calling vfs_follow_link(), but there's no point to that.
Let's use page_follow_link_light() and nd_set_link().

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>