Add testDBClientAction::test_getNewActionId().

This current version of Hatohol fails the added test with the following message.
  testDBClientAction::test_getNewActionId:              terminate called after throwing an instance of 'HatoholException'
  what():  <DBAgentMySQL.cc:349> Failed to query: SELECT action_id FROM actions ORDER BY DESC LIMIT 1 : You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'DESC LIMIT 1' at line 1