VOP_DELETEEXTATTR
error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, NOCRED);
error = VOP_DELETEEXTATTR(vp, attrnamespace, attrname, l->l_cred);
error = VOP_DELETEEXTATTR(vp, attrnamespace, name, cred);
int VOP_DELETEEXTATTR(struct vnode *, int, const char *, kauth_cred_t);