installer: remove liveuser from /etc/sudoers in local installation.

Close #43

installer.sh.in

@@ -856,6 +856,7 @@ ${BOLD}Do you want to continue?${RESET}" 20 80 || return
         # Remove live user.
         echo "Removing $USERNAME live user from targetdir ..." >$LOG
         chroot $TARGETDIR userdel -r $USERNAME >$LOG 2>&1
+        sed -i -e "/$USERNAME ALL=.*/d" $TARGETDIR/etc/sudoers
         DIALOG --title "Check $LOG for details" \
             --infobox "Rebuilding initramfs for target ..." 4 60
         echo "Rebuilding initramfs for target ..." >$LOG