OGM-558 Remove early access repository

https://hibernate.atlassian.net/browse/OGM-558

  The repository is used only to downaload EAP 6.1, but the
  version downloaded is quite old and we don't need to support it.

  At the moment there is not a EAP 6.2 version on the repository,
  the only way to run the integration test is to have an
  installation somewhere.