[Server][ArmZabbixAPI] Remove a function: updateHosts(const ItemTable
*triggers)

Because, this function doesn't need.

Current mechanism of retrive host information get from only host id which is
included in triggers ItemTable.
But, I want to retrieve hostgroup id which is include in host.
An interval of current mechanism is very long.
(In some Cases, host and hostgroup id don't update.)
[Server][ArmZabbixAPI] Change the way of retrieving hostgroup id which is
included in host id.