allow predictable network interfaces

on dual-eth-raspi:
- eth0 -> end0
- eth1 -> enx...

sethostname.sh

@@ -1,4 +1,8 @@
-ETHNAME=$(cat /sys/class/net/eth0/address)
+if [[ -f /sys/class/net/eth0/address ]]; then
+  ETHNAME=$(cat /sys/class/net/eth0/address)
+else
+  ETHNAME=$(cat /sys/class/net/end0/address)
+fi
 FOUND=($(grep -l -r MAC=$ETHNAME /home/l_samenv/boxtools/cfg))
 if [ -z "$FOUND" ]; then
    BOXID=${ETHNAME//:/}