Avoid too fast restarting of web server while renewing LetsEncrypt

Fix hestiacp#1193

Author: myvesta

bin/v-update-letsencrypt-ssl

@@ -52,6 +52,7 @@ for user in $users; do
                 $BIN/v-add-letsencrypt-domain $user $domain
             fi
         fi
+        sleep 10
     done
 done