The logo of the Organization of the Petroleum Exporting Countries (OPEC) is pictured at its headquarters in Vienna, Austria, May 30, 2016. REUTERS/Heinz-Peter Bader

A Muslim woman wears a burkini, a swimsuit that leaves only the face, hands and feet exposed, on a beach in Marseille, France, August 17, 2016. REUTERS/Stringer/File Photo

A car is filled with gasoline at a gas station pump in Carlsbad, California August 4, 2015. REUTERS/Mike Blake

Congolese opposition supporters chant slogans during a march to press President Joseph Kabila to step down in the Democratic Republic of Congo's capital Kinshasa, September 19, 2016. REUTERS/Kenny Katombe

Congolese opposition supporters chant slogans as they destroy the billboard of President Joseph Kabila during a march to press the President to step down in the Democratic Republic of Congo's capital Kinshasa, September 19, 2016. REUTERS/Kenny Katombe

Austrian Chancellor Christian Kern arrives for a cabinet meeting in Vienna, Austria August 30, 2016. REUTERS/Heinz-Peter Bader

REFILE - ADDITIONAL CAPTION INFORMATION Former Serb paramilitary commander Dragan Vasiljkovic (C), known as Captain Dragan and accused of torturing and killing soldiers and civilians during the 1991-95 independence war, goes on trial in court in Split, Croatia, September 20, 2016. PIXSELL/Ivo Cagalj/via REUTERS

Senator Bukola Saraki looks on after being elected as the senate president of the 8th Nigeria Assembly in Abuja, Nigeria June 9, 2015. REUTERS/Afolabi Sotunde