Failure to provide property tax relief is shaping up as a potentially damaging issue for Gov. Ed Rendell, whose Republican challengers have gained some ground on the Democratic incumbent, the independent Quinnipiac (KWIN uh-pe-ack) University poll finds. Former Lt Gov. Bill Scranton has narrowed the gap from 15 points April 21 to 10 points today. Pennsylvania voters give Gov. Ed Rendell a 47 - 39 percent approval rating, his lowest since a 46 - 33 percent approval in an April 22, 2004, Quinnipiac University poll. The Governor deserves to be reelected, voters say 46 - 41 percent, down from 48...