improve spec test for zabbix::repo
improve spec test for zabbix::repo

Co-authored-by: Christos Papageorgiou <ed44e2cc434f7f0ad18cc785f0d3e7467d67aff7@gmail.com>
voxpupuli/puppet-zabbix,voxpupuli/puppet-zabbix,voxpupuli/puppet-zabbix