CRM-15644,CRM-15693 - fix civicrm_group table missing error on login when CiviCRM ...

...DB is separate from Drupal's

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* CRM-15644: civicrm_group table "missing" error on login when CiviCRM DB is separate from Drupal's
  https://issues.civicrm.org/jira/browse/CRM-15644