Hatohol arm plugin ceilometer c++ 7

These patches send events (alarm history) of ceilometer to Zabbix server.

We can see them in Web UI, althogh host names are not correctly shown.
As for taking care of host names, I will do it as a next step.
When the ret is transport error (ret < 100), it's hard to recognize the detail  because it's not well-known
HTTP error, it's soup specific error.

How about using soup_status_get_phrase()?

https://developer.gnome.org/libsoup/unstable/libsoup-2.4-soup-status.html#soup-status-get-phrase