Fix an issue with service(8) where utilities such as screen(1) and tmux(1)

would behave differently when utilizing rc-script was invoked manually vs.
service(8). The issue being that these utilities require the TERM environ
variable to be set and service(8) was not passing it down.

Reported by:	Michael Dexter <editor@callfortesting.org>
PR:		bin/191869
Reviewed by:	allanjude
MFC after:	3 days
X-MFC-to:	stable/10, stable/9

usr.sbin/service/service.sh

@@ -139,7 +139,7 @@ cd /
 for dir in /etc/rc.d $local_startup; do
 	if [ -x "$dir/$script" ]; then
 		[ -n "$VERBOSE" ] && echo "$script is located in $dir"
-		exec env -i HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin $dir/$script $*
+		exec env -i HOME=/ PATH=/sbin:/bin:/usr/sbin:/usr/bin TERM="$TERM" $dir/$script $*
 	fi
 done