[DBTablesMonitoring] Change the attributes of DB Index (EventID).

Index Name :EventsUniqId -> EventsId
Allow duplicate registration of event ID, in order to register monitoring server's failure.
If there is a old index EventsUniqId, EventsUniqId is deleted to after EventsId registration.
[test][DBTable] Add test case of duplicate registration of event ID.
[DBTablesTest] delete comment and unnecessary element.

Defunct server was unnecessary.
[testDBTablesMonitoring] modified the parameter of function.

fixtures and numberOfFixtures pass as a parameter, and setting to
testEventInfo and NumTestEventInfo as the default value .
[DBTablesTest] delete comment.

I forgot to delete a comment in the previous commit.
Merge pull request #490 from project-hatohol/fix-events-regist-failure

Fix the failure of events registration(monitoring server's failure, etc.).