Fix zabbix::proxy idempotency
Fix zabbix::proxy idempotency

Active proxies don't use `ipaddress`, `use_ip` or `port`.  Specifically,
the zabbix_proxy provider will return `nil` for these properties for
active proxies.

voxpupuli/puppet-zabbix,voxpupuli/puppet-zabbix,voxpupuli/puppet-zabbix