A disabled ­Alta Sierra veteran was sentenced to 90 days in jail and three years probation after pleading no contest to assault with a deadly weapon. Nicholas Joseph Severin, 36, was arrested after allegedly throwing knives at his son, then baiting law enforcement officers to shoot him in an April 2012 incident. Severin’s 17-year-old stepson had called 911 to report his father was coming after him with a knife. The boy told deputies his father had been punching his mother, and he tried to intervene. The two fought before the father grabbed some knives, then began throwing them at the …