UPDATE 4-Mexico opposition wins key state vote, boosting reform outlook

* PAN victory to defuse tensions over cross-party accord* Conservatives still willing to push for reforms* Pena Nieto seeks overhaul of Pemex, changes in tax systemBy Dave Graham and Miguel GutierrezMEXICO CITY, July 8 (Reuters) – Mexican President Enrique Pena Nieto’s economic...UPDATE 4-Mexico opposition wins key state vote, boosting reform outlook