Uninitialized kernel stack memory leaked via acl_get_file/acl_get_fd

Summary

vacl_get_acl declares struct acl inkernelacl on stack without zeroing(:92). VOP_GETACL writes acl_cnt entries. copyout(:99) copies ENTIRE struct including entries [acl_cnt..31] uninitialized. Latent: no in-tree FS implements VOP_GETACL (vfs_default.c:89 vop_eopnotsupp). Live immediately if ACL-capable FS added.