Auto remove child services after deassoc

[VitalyWhite]

After use deassoc stay associated child services and they must be removed manually.

Example:

root@zabbix-test:~# itsvc ls 425
=> Test_child (h10084) [425]
0| /etc/passwd has been changed on Zabbix server [495]
0| Configured max number of opened files is too low on Zabbix server [505]
...

root@zabbix-test:~# itsvc deassoc 425
{
   "result" : "1"
}

root@zabbix-test:~# itsvc ls 425
=> Test_child [425]
0| /etc/passwd has been changed on Zabbix server [495]
0| Configured max number of opened files is too low on Zabbix server [505]
...