othermta: remove leftover from 20 years ago

othermta (along with mta_start_script configuration entry in rc.conf)
was a mechanism used to be able to run another mta than sendmail(8) before
"rcng" time 20 years ago.

othermta has not been used since.

libexec/rc/rc.conf

@@ -593,8 +593,6 @@ allscreens_kbdflags=""	# Set this kbdcontrol mode for all virtual screens
 ###  Mail Transfer Agent (MTA) options  ######################
 ##############################################################
 
-mta_start_script="/etc/rc.sendmail"
-			# Script to start your chosen MTA, called by /etc/rc.
 # Settings for /etc/rc.d/sendmail:
 sendmail_enable="NO"	# Run the sendmail inbound daemon (YES/NO/NONE).
 			# If NONE, don't start any sendmail processes.

libexec/rc/rc.d/Makefile

@@ -255,10 +255,6 @@ VAR_HEMIDAL=	/var/heimdal
 VAR_HEMIDAL_MODE=	700
 .endif
 
-.if ${MK_MAIL} != "no"
-CONFS+=		othermta
-.endif
-
 .if ${MK_NS_CACHING} != "no"
 _nscd=		nscd
 .endif

libexec/rc/rc.d/othermta

@@ -1,18 +0,0 @@
-#!/bin/sh
-#
-# $FreeBSD$
-#
-
-# PROVIDE: mail
-# REQUIRE: LOGIN
-
-# XXX - TEMPORARY SCRIPT UNTIL YOU WRITE YOUR OWN REPLACEMENT.
-#
-. /etc/rc.subr
-
-load_rc_config
-
-if [ -n "${mta_start_script}" ]; then
-	[ "${mta_start_script}" != "/etc/rc.sendmail" ] && \
-	    sh ${mta_start_script} "$1"
-fi