Update metadata.rb
Update metadata.rb

yum dependency was in twice.
paybyphone/zabbix-agent,TD-4242/cookbook-zabbix-server,paybyphone/zabbix-agent,TD-4242/cookbook-libzabbix,TD-4242/zabbix-agent,TD-4242/zabbix-agent,TD-4242/cookbook-zabbix-server,paybyphone/zabbix-agent,TD-4242/cookbook-zabbix-server,TD-4242/cookbook-libzabbix,TD-4242/zabbix-agent