Don't use FS namespaces for the agent

While they are a bit better security wise, it makes false vfs.fs.discovery results, including duplicated entries (for /tmp for example)

zabbix-agent.service

@@ -9,12 +9,9 @@ PIDFile=/var/run/zabbix/zabbix_agentd.pid
 Restart=always
 User=zabbix
 Group=zabbix
-PrivateTmp=yes
 CPUShares=512
 MemoryLimit=150M
 BlockIOWeight=500
-InaccessibleDirectories=/home
-ReadOnlyDirectories=/etc /usr
 
 [Install]
 WantedBy=multi-user.target