Incorrect messaging if crashing out of script at 0 deferrals

[grahampugh]

When you get to the no deferrals left pane and then crash out the script it then goes back to X deferrals left message, but without any number displayed.

(lines 154-156)

    if [[ "$notificationCount" -ge "$maxNotificationCount" ]]; then
        writelog "$loggedInUser has been notified $notificationCount times; not waiting any longer."
        alert_user "$notificationsLeft remaining alerts before auto-install." "$notificationCount"

(reported in Slack by Peter Lewis)