Throughout drop allow_ntsec and allow_smbntsec handling.

	Throughout drop allow_ntsec and allow_smbntsec handling.
	* environ.cc (set_ntsec): Remove.
	(set_smbntsec): Remove.
	(known): Remove ntsec and smbntsec options.
	* external.cc (check_ntsec): Return true if no filename is given.
	* mount.cc (oopts): Add "acl" and "noacl" options.  Set MOUNT_NOACL
	flag accordingly.
	(fillout_mntent): Handle MOUNT_NOACL flag.
	* path.h (enum path_types): Add PATH_NOACL.
	* security.cc (allow_ntsec): Remove.
	(allow_smbntsec): Remove.
	* security.h (allow_ntsec): Drop declaration.
	(allow_smbntsec): Drop declaration.
	* include/sys/mount.h (MOUNT_NOACL): Define.