CRM-14151 add hacky-handling to receive date like other date fields in completetransaction function to mitigate DAO->find() followed by DAO->save() fatalling on date fields .. sometimes

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* CRM-14151: BaseIPN fails when receipt_date is set
  http://issues.civicrm.org/jira/browse/CRM-14151
Merge pull request #2444 from eileenmcnaughton/CRM-14151

CRM-14151 add hacky-handling to receive date like other date fields in c...