The 90-year-old man mauled by a neighbor's pit bulls yesterday morning had his left leg amputated. Henry Piotrowski's niece said he will probably lose one of his arms. The dogs belonged to James McNair, a registered sex offender, who was charged with, per the Staten Island Advance, "having unlicensed dogs, not having his dogs on a leash and fireworks possession." Neighbors say that they have called 311 and the police repeatedly about the pit bulls,......