Commodity markets posted their biggest rally for the year on Friday, with oil prices rocketing 9%, as a long-awaited debt deal in Europe pushed buyers back into a sector that had logged few gains since May. The rally on the final trading day of June saved commodities from posting their worst quarterly loss since the onset of the financial crisis in 2008. The 8% drop for the quarter on the Thomson Reuters-Jefferies CRB index for commodities was