Diamond Offshore Drilling Inc, one of the world's top five offshore rig contractors, reported a better-than-expected quarterly profit as it cut drilling costs and hiked prices, sending its shares up as much as 10.5 percent. The company - owned 50.4 percent by hotel, energy and financial services conglomerate Loews Corp - also said it would pay a special cash dividend of 75 cents per share on top of its regular quarterly dividend of 13 cents. Diamond Offshore, which has one of the oldest fleet of rigs…