Fix for non-broadcasting WiFi SSIDs

[acostein]

For those who have WiFi networks whose SSIDs are not broadcast, the instructions don't work as written, but a simple change fixes it...

setup-piForHeadlessConfig.sh adds a network={...} section to the wpa_supplicant.conf file it creates. If you add "scan_ssid=1" to the network={} section near the end of setup-piForHeadlessConfig.sh, non-broadcast SSIDs will be found as well.