Swiss drugmaker Roche (ROG.VX) gave a bullish forecast for the next two years after its $47 billion acquisition of Genentech and said it would expand capacity for H1N1 flu drug Tamiflu.Roche missed forecasts with a 29 percent drop in first-half net profit on Thursday, hit by costs related to the Genentech purchase earlier this year, but its stock rose thanks to the strength of its underlying business.The world's largest maker of cancer drugs upped its earnings guidance and now expects double-dig