Remove support for rlogind in login(1), that is, remove the '-r' flag

The "quick hack" finally disappeared.  Probably nobody noticed.  ;)
(See the changes in <configure.ac> for the context of this pun.)

Probably everybody uses SSH these days for remote login.  Let's remove
this insecure method.

Closes: <https://github.com/shadow-maint/shadow/issues/992>
Reviewed-by: dkwo <nicolopiazzalunga@gmail.com>
Reviewed-by: Iker Pedrosa <ipedrosa@redhat.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Michael Vetter <jubalh@iodoru.org>
Cc: Sam James <sam@gentoo.org>
Cc: Benedikt Brinkmann <datacobra@thinkbot.de>
Signed-off-by: Alejandro Colomar <alx@kernel.org>

tests/bug332198-test.exp

@@ -1,61 +0,0 @@
-#!/usr/bin/expect -f
-
-# This is a script for repeatedly logging into the localhost
-# using `rlogin` in order to apparently see a symptoms described
-# in bug #332198.
-# As described in the bug log, sometimes `rlogind` will fail to
-# establish a connection, because it starts "login" process and
-# the latter fails with "unable to determine TTY name, got /dev/pts/1"
-# message.
-# 
-# BUGS
-# 
-# * the script rlogins to localhost
-# * the script doesn't handle passwdord prompt, because it's intended
-#   to use .rhosts auth and expects shell prompt immediately after
-#   `rlogin`
-# * the regexp for shell prompt is hardcoded
-
-log_user 0
-match_max 8192
-
-while {1} {
-    set rlogin_spawn [spawn rlogin localhost]
-    if { $rlogin_spawn == 0 } { exit 1 }
-    expect {
-	-timeout 10 -re "^.*(Last login\[^\r\n\]*).*\n(\[^\r\n\]*\[#$\] )$" {
-	    send_error "$expect_out(1,string)\n"
-	    send_error "$expect_out(2,string)\n"
-#	    send_error "$expect_out(0,string)\n"
-	}
-	timeout {
-	    send_error "TIMEOUT/prompt\n"
-	    send_error "$expect_out(buffer)\n"
-	    send_error "RETRYING\n"
-	    log_user 1
-	    send "tty /\r"
-	    expect -timeout 2 -re "^.*\r?\n(\[^\r\n\]*# )$" {}
-	    send "tty /\r"
-	    expect -timeout 2 -re "^.*\r?\n(\[^\r\n\]*# )$" {}
-	    send_error "\n"
-	    exit 2
-	}
-    }
-    send "tty\r"
-    expect {
-	-timeout 4 -re "tty\r?\n(\[^\r\n\]*)\r?\n(\[^\r\n\]*\[#$\] )$" {
-	    send_error "$expect_out(2,string)$expect_out(1,string)\n"
-#	    send_error "$expect_out(0,string)\n"
-	}
-	timeout { send_error "TIMEOUT/tty\n" ; exit 3 }
-    }
-    send "exit\r"
-    expect {
-	-timeout 2 eof {
-#	    send_error "OK4: EOF\n"
-	}
-	timeout { send_error "TIMEOUT/eof\n" ; exit 4 }
-    }
-    wait
-}
-# vi: set sw=4: