BAZ RATNER and SHAFIEK TASSIEM RWANDAN forces patrolled burnt-out streets once besieged by Islamist fighters in northern Mozambique, saying it was now safe for civilians to return to the gas-rich region, despite U.N. warnings of a continuing militant threat. Soldiers laid out rifles and rocket launchers seized from the militants. The Rwandan military's spokesman said they had already brought 25,000 people back home. "It is very safe for them to go back," Ronald Rwivanga told Reuters. In July, allied Rwandan-Mozambican troops moved in to recapture parts of northern Cabo Delgado - an area hosting $60 billion worth of gas projects…