fix Spec deprecation warning under rails 2
fix Spec deprecation warning under rails 2

Baltazore/formtastic,nishaya/formtastic,EndingChaung/formtastic,paulodiovani/formtastic,justinfrench/formtastic,crashlytics/formtastic,ryanfox1985/formtastic,EndingChaung/formtastic,justinfrench/formtastic,thenthen8515/formtastic,sideci-sample/sideci-sample-formtastic,nishaya/formtastic,ConferenceCloud/formtastic,Guestfolio/formtastic,ryanfox1985/formtastic,mikz/formtastic,ConferenceCloud/formtastic,justinfrench/formtastic,Guestfolio/formtastic,thenthen8515/formtastic,Davidzhu001/formtastic,Davidzhu001/formtastic,paulodiovani/formtastic,mikz/formtastic,ryanfox1985/formtastic