Minor bug fix of v-sync-dns-cluster

Problem Outlined: It seems that another script has dropped a file called history.log into the $VESTA/data/users folder causing v-sync-dns-cluster to throw a soft error about not finding /usr/local/vesta/data/users/history.log/dns.conf when syncing zones.

Fix: Tell the script to ignore that log file when syncing user domains and the output becomes clean.

bin/v-sync-dns-cluster

@@ -49,7 +49,7 @@ for cluster in $hosts; do
     check_result $? "$HOST connection failed" $E_CONNECT
 
     # Syncing user domains
-    user_list=$(ls $VESTA/data/users |grep -v "dns-cluster")
+    user_list=$(ls $VESTA/data/users |grep -v "dns-cluster" |grep -v "history.log")
     for user in $user_list; do
         for str in $(cat $VESTA/data/users/$user/dns.conf); do