Keaira Bennefield’s estranged husband — who now stands accused of killing her with a shotgun — somehow obtained an order of protection against her after he savagely beat the mom of three in their home, The Post has learned. The stunning new details behind the Buffalo woman’s shocking Oct. 5 slaying are contained in an official transcript of ex-con Adam Bennefield’s arraignment in the vicious, caught-on-camera beating inside their home — less than a week before cops say he gunned down his wife. Keaira, 30, said that Adam Bennefield, 45, “told me to ‘shut the --- up’ and that he...