* Fund built on revenues from domestic oil, gas industry (Adds quote, background, bullet points): OSLO (Reuters) - Norway’s trillion-dollar sovereign wealth fund should continue to invest in oil and gas companies, a government-appointed commission recommended on Friday, contradicting earlier advice from the central bank. A decision on whether to drop energy shares from the fund’s benchmark index, and thus divest tens of billions of dollars from oil and gas stocks over time, is expected this autumn.