bsdinstall: rename "Live CD" to "Live System"

This uses more generic wording in the FreeBSD installer, when offering
the user to use the system booted without running the installer.

The updated wording is also reflected in freebsd-version(1).

Reviewed by:		emaste
Sponsored by:		The FreeBSD Foundation
Differential revision:	https://reviews.freebsd.org/D43233

bin/freebsd-version/freebsd-version.1

@@ -111,7 +111,7 @@ To determine the version of the currently running userland:
 /bin/freebsd-version -u
 .Ed
 .Pp
-To inspect a system being repaired using a live CD:
+To inspect a system being repaired using a live system:
 .Bd -literal -offset indent
 mount -rt ufs /dev/ada0p2 /mnt
 env ROOT=/mnt /mnt/bin/freebsd-version -ku

usr.sbin/bsdinstall/startbsdinstall

@@ -57,7 +57,7 @@ if [ -f /etc/installerconfig ]; then
 	exit 
 fi
 
-bsddialog --backtitle "FreeBSD Installer" --title "Welcome" --extra-button --extra-label "Shell" --ok-label "Install" --cancel-label "Live CD" --yesno "Welcome to FreeBSD! Would you like to begin an installation or use the live CD?" 0 0
+bsddialog --backtitle "FreeBSD Installer" --title "Welcome" --extra-button --extra-label "Shell" --ok-label "Install" --cancel-label "Live System" --yesno "Welcome to FreeBSD! Would you like to begin an installation or use the live system?" 0 0
 
 case $? in
 $BSDDIALOG_OK)	# Install
@@ -70,7 +70,7 @@ $BSDDIALOG_OK)	# Install
 	trap true SIGINT	# Ignore cntrl-C here
 	bsdinstall
 	if [ $? -eq 0 ]; then
-		bsddialog --backtitle "FreeBSD Installer" --title "Complete" --ok-label "Reboot" --extra-button --extra-label "Shutdown" --cancel-label "Live CD" --yesno "Installation of FreeBSD complete! Would you like to reboot into the installed system now?" 0 0
+		bsddialog --backtitle "FreeBSD Installer" --title "Complete" --ok-label "Reboot" --extra-button --extra-label "Shutdown" --cancel-label "Live System" --yesno "Installation of FreeBSD complete! Would you like to reboot into the installed system now?" 0 0
 
 		case $? in
 		$BSDDIALOG_OK)		# Reboot
@@ -90,15 +90,15 @@ $BSDDIALOG_OK)	# Install
 				sleep 1
 			done
 			;;
-		$BSDDIALOG_CANCEL)	# Live CD
+		$BSDDIALOG_CANCEL)	# Live System
 			exit 0
 			;;
 		esac
 	else
 		. "$0"
 	fi
 	;;
-$BSDDIALOG_CANCEL)	# Live CD
+$BSDDIALOG_CANCEL)	# Live System
 	exit 0
 	;;
 $BSDDIALOG_EXTRA)	# Shell