Remove invalid remark about pipes.

The stat structures returned on pipes seems to contain all the
information required by POSIX. Especially the wording "and thus to a
pipe" makes little sense, because it seems to imply a certain
relationship between sockets and pipes that simply isn't there.

MFC after:	2 weeks

lib/libc/sys/stat.2

@@ -28,7 +28,7 @@
 .\"     @(#)stat.2	8.4 (Berkeley) 5/1/95
 .\" $FreeBSD$
 .\"
-.Dd November 17, 2011
+.Dd June 2, 2012
 .Dt STAT 2
 .Os
 .Sh NAME
@@ -431,7 +431,7 @@ system call appeared in
 .Sh BUGS
 Applying
 .Fn fstat
-to a socket (and thus to a pipe)
+to a socket
 returns a zeroed buffer,
 except for the blocksize field,
 and a unique device and inode number.