[Client][TestUtils] Add test assertions to new function.
[Client][Utils] Add case for nagios.
[Client][TestUtils] Add new test item for unknown server type.
[Client][TestUtils] Use defined value.

0 ->
hatohol.MONITORING_SYSTEM_ZABBIX

1 ->
hatohol.MONITORING_SYSTEM_NAGIOS
[Client][Utils] Prepare the commonly used function.
[Server][tools][HatoholDefSrcFileGenerator] Add new defined value:
MONITORING_SYSTEM_UNKNOWN
[Client][TestUtils] Use defined value.
Merge pull request #226 from project-hatohol/issue209

Issue209 - 1