Remove some more leftover rlogin man page xrefs

rcmds were removed in r32435 and these three man pages can trivially
drop the references.

There's still a reference in pts.4 because it describes a mode
(TIOCPKT_NOSTOP), and only lists rlogin/rlogind as examples of programs
that use that mode.  To update later.

MFC after:	1 week
Sponsored by:	The FreeBSD Foundation

share/man/man4/termios.4

@@ -58,9 +58,7 @@ a connection being present.
 In practice, applications
 seldom open these files; they are opened by special programs, such
 as
-.Xr getty 8
-or
-.Xr rlogind 8 ,
+.Xr getty 8 ,
 and become
 an application's standard input, output, and error files.
 .Ss Job Control in a Nutshell

share/man/man4/tty.4

@@ -54,8 +54,6 @@ These special terminal devices are called
 .Em ptys
 and provide the mechanism necessary to give users the same interface to the
 system when logging in over a network (using
-.Xr rlogin 1 ,
-or
 .Xr telnet 1
 for example).
 Even in these cases the details of how the terminal

share/man/man5/hosts.equiv.5

@@ -127,8 +127,6 @@ except users from netgroup
 .Dq dau .
 .Sh SEE ALSO
 .Xr rcp 1 ,
-.Xr rlogin 1 ,
-.Xr rsh 1 ,
 .Xr gethostbyname 3 ,
 .Xr inet 3 ,
 .Xr innetgr 3 ,