A sheriff’s deputy’s killer, whose 1985 grant of clemency from New York Gov. Mario M. Cuomo was denounced by then-Vice President George Bush, has been granted parole. The decision to release Gary McGivern, convicted of murder in the 1968 shooting, followed his appearance before a three-member Board of Parole panel at the medium-security prison in Otisville where he is serving a life sentence. It was McGivern’s third parole board appearance since Cuomo’s grant of clemency, which made him eligible for an immediate parole hearing. Twice McGivern was turned down because of the nature of the crime.