By Larry Fine SPRINGFIELD, New Jersey (Reuters) - Unheralded Robert Streb fired a record-equaling 63 to share a two-shot lead with Jimmy Walker after the second round of the PGA Championship on Friday, with heavyweights Jason Day and Henrik Stenson lurking nearby. Streb, who has one PGA Tour victory, rolled in a 20-foot birdie putt on his last hole, the ninth at Baltusrol, for the 30th round of 63 ever shot in a major championship. "Most of the year has been a big struggle," said 29-year old Streb, who won the McGladrey Classic two years ago but has missed nine cuts this year including the Masters, U.S. Open, British Open and The Players. More...