A new report says the city’s public housing authority wasted millions paying for roof repairs that should have been covered under a warranty — and may still cost the agency an additional $24 million in replacements. According to a new audit from New York City Comptroller Scott Stringer’s office, covering 2000 to 2010, the New York City Housing Authority ignored roof warranties on more than 98 percent of its work orders. The housing agency was found to only have used its roof-warranty coverage on just 1.3 percent of the roof repairs – instead using public…