The dhcp-server config mode script does a test run of the config file, given the fragility of passing 'raw' options (T3544); the test file is '/tmp/dhcpd.conf' and is not removed after generation. This file, unfortunately, is misinterpreted by the zabbix-agent smoketest, causing a failure when smoketests are run in batch.
The dhcp-server should clean up after generation of the config file; that is fixed here.