By Andrew Mills and Ghaida Ghantous DOHA (Reuters) – U.S. Special Envoy for Iran Robert Malley said on Sunday he was not confident that a nuclear deal between world powers and Iran was imminent, dampening expectations after 11 months of talks in Vienna that have stalled. The failure of efforts to restore the pact, which would curb Tehran’s nuclear programme in exchange for lifting tough sanctions, could carry the risk of a regional war, or lead to more harsh Western sanctions and further rises in world oil prices, analysts say. “I can’t be confident it is imminent.. a few months ago we thought…