Zabbix agent 2 persistent buffer is broken

[badfiles]

The enable parameter is missing in agent template

c2a32d5#r142464773

[badfiles]

now the zabbix_agent_persistentbuffer var is missing in the rest of the code

[Troy W.]

@badfiles take a look at #1278 and tell me if I actually fixed this finally

[badfiles]

yes, now it works