Steps to reproduce:

1. Install zabbix-agent via pkg
2. Modify file `/usr/local/etc/zabbix/zabbix_agentd.conf`
3. Re-install zabbix agent via pkg

Result:

Extra unnecessary files will be left by second installer: `/usr/local/etc/zabbix/zabbix_agentd/userparameter_{examples,mysql}.conf.NEW` while their  counterparts (without '.NEW' suffix is identical to them)

Expected:
No such files

How to Fix:

Replace line 37 of postinstall scripts (`cmp --silent "${file_new}" "${file}" || ret=$?`) with `cmp --silent "${file_new}" "${file}"; ret=$?`

What happens is `ret` variable reused in cycle and not set to zero on next loop.