title: Email validation changed upgrading from grails 2.0.0 to 2.4.3
body: <p>My project recently upgraded grails from 2.0.0 to 2.4.3.  In a domain object I am using the email validation constraint.  I've noticed in testing that emails with fake tlds eg 'fake@fakedomain.tld' are now considered invalid.  Grails documentation says it is using Apache Commons EmailValidation class to do the validating.  That documentation explicitly states that it <a href="http://commons.apache.org/proper/commons-validator/apidocs/org/apache/commons/validator/routines/EmailValidator.html" rel="nofollow">doesn't check for valid tlds</a>.</p>
  
  <p>Has anyone else seen this issue, and if so was there a simple work around?  I am on the fence between a custom validator that allows invalid tlds or removing the constraint all together.</p>