CRM-12272 Fixed logic so that form rule ensures that EITHER custom_pre O...

...R custom_post is an individual profile. Previously the code was throwing form rule error when custom_post was NOT type individual even though custom_pre was. However, the complete fix is to check for first + last name profile fields when Allow multiple registrations from same email is checked. Will file issue for that for 4.4.

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* CRM-12272: Validation for required profile fields in event registration ignores 'extra' profiles
  http://issues.civicrm.org/jira/browse/CRM-12272