Randomize cron timings for freedns updates

This avoids creating a fingerprint for freedombone installs

src/freedombone-utils-dns

@@ -129,8 +129,19 @@ function freedns_update_cron {
             ddns_code=$(grep 'DEFAULT_DOMAIN_CODE=' "$CONFIGURATION_FILE" | awk -F '=' '{print $2}')
             if [ "$ddns_code" ]; then
                 if [ ${#ddns_code} -gt 10 ]; then
-                    # TODO randomise these timings
-                    echo "3,8,13,18,23,28,33,38,43,48,53,58 * * * * root sleep 46 ; wget --no-check-certificate -O - https://freedns.afraid.org/dynamic/update.php?${ddns_code}= >> /var/log/freedns_@_update.log 2>&1 &" >> /etc/crontab
+                    dns_update1=$(shuf -i 1-7 -n 1)
+                    dns_update2=$(shuf -i 8-12 -n 1)
+                    dns_update3=$(shuf -i 13-17 -n 1)
+                    dns_update4=$(shuf -i 18-22 -n 1)
+                    dns_update5=$(shuf -i 23-27 -n 1)
+                    dns_update6=$(shuf -i 28-32 -n 1)
+                    dns_update7=$(shuf -i 33-37 -n 1)
+                    dns_update8=$(shuf -i 38-42 -n 1)
+                    dns_update9=$(shuf -i 43-47 -n 1)
+                    dns_update10=$(shuf -i 48-52 -n 1)
+                    dns_update11=$(shuf -i 53-56 -n 1)
+                    dns_update12=$(shuf -i 57-59 -n 1)
+                    echo "${dns_update1},${dns_update2},${dns_update3},${dns_update4},${dns_update5},${dns_update6},${dns_update7},${dns_update8},${dns_update9},${dns_update10},${dns_update11},${dns_update12} * * * * root sleep 46 ; wget --no-check-certificate -O - https://freedns.afraid.org/dynamic/update.php?${ddns_code}= >> /var/log/freedns_@_update.log 2>&1 &" >> /etc/crontab
                 fi
             fi
         fi