zabbix-agent: Switch to FQDN

Signed-off-by: Florian Pritz <bluewind@xinu.at>

roles/zabbix-agent/templates/zabbix_agentd.conf

 LogType=system
 Server={{zabbix_agent_server}}
 ServerActive={{zabbix_agent_server}}
-Hostname={{ansible_hostname|lower}}
+Hostname={{inventory_hostname|lower}}
 #Include=/etc/zabbix/zabbix_agentd.conf.d/*.conf
 
 TLSConnect=psk
 TLSAccept=psk
-TLSPSKIdentity=PSK{{ansible_hostname|lower}}
+TLSPSKIdentity=PSK{{inventory_hostname|lower}}
 TLSPSKFile=/etc/zabbix/zabbix_agentd.psk
 
 UserParameter=mysql.ping,mysqladmin --defaults-file="/etc/zabbix/zabbix_agentd.my.cnf" ping|grep alive|wc -l