when using SHA1Data(), no CTX is needed, so zap that line in the example

ok jmc@

src/lib/libc/hash/sha1.3

@@ -1,4 +1,4 @@
-.\"	$OpenBSD: sha1.3,v 1.34 2004/06/22 01:57:29 jfb Exp $
+.\"	$OpenBSD: sha1.3,v 1.35 2006/10/03 12:06:07 grunk Exp $
 .\"
 .\" Copyright (c) 1997, 2004 Todd C. Miller <Todd.Miller@courtesan.com>
 .\"
@@ -188,7 +188,6 @@ putchar('\en');
 .Pp
 Alternately, the helper functions could be used in the following way:
 .Bd -literal -offset indent
-SHA1_CTX sha;
 u_int8_t output[SHA1_DIGEST_STRING_LENGTH];
 char *buf = "abc";