UPDATE 1-UAE's Etisalat will not re-bid for Zain - exec

* Etisalat scrapped takeover of Zain in March * Cited Zain's divided board, due diligence, regional unrest (Adds further quotes, background) (Adds details, quotes) By Matt Smith DUBAI, May 10 (Reuters) - UAE's Etisalat (ETEL.AD "We have put Zain behind...