REYNOSA, Mexico (Reuters) - The oil and gas fracking boom has lured scores of drillers to the Eagle Ford region of South Texas, the second largest U.S. oil patch, as new production technology opened access to billions more barrels. FILE PHOTO: Soldiers keep guard a gas facility of Pemex in Reynosa September 18, 2012. REUTERS/Daniel Becerril/File PhotoThe play extends across the Mexican border, where its name changes to the Burgos Basin – an equally fertile shale region where the oil and gas sit mostly idle underground in a region terrorized by criminal gangs.The violence . . .