Remove lies about openpty(4) searching for a free pseudo-tty by iterating

through all existing pseudo-tty devices in /dev.

src/lib/libutil/openpty.3

@@ -1,4 +1,4 @@
-.\"	$OpenBSD: openpty.3,v 1.16 2013/06/05 03:40:26 tedu Exp $
+.\"	$OpenBSD: openpty.3,v 1.17 2015/08/28 19:54:06 kettenis Exp $
 .\" Copyright (c) 1995
 .\"	The Regents of the University of California.  All rights reserved.
 .\"
@@ -30,7 +30,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: June 5 2013 $
+.Dd $Mdocdate: August 28 2015 $
 .Dt OPENPTY 3
 .Os
 .Sh NAME
@@ -79,21 +79,15 @@ is non-null, the window size of the slave will be set to the values in
 .Pp
 The
 .Fn openpty
-function works in the following way:
-first it attempts to allocate the pseudo-tty through the
+function allocates the pseudo-tty through the
 .Pa /dev/ptm
 device (see
 .Xr pty 4
-for details) and if that fails it searches for a free pseudo-tty by iterating
-through all existing pseudo-tty devices in
-.Pa /dev .
-When a free pseudo-tty is found, its ownership is changed to
-the UID of the caller, permissions are set to correct values,
-and all earlier uses of that device are revoked (see
+for details) which means that its ownership is changed to the UID of
+the caller, permissions are set to correct values, and all earlier
+uses of that device are revoked (see
 .Xr revoke 2
 for details).
-The first method can work for any user, the second method requires
-super-user privileges in most cases.
 .Pp
 The
 .Fn login_tty