johannesburg south african president jacob zuma congratulate emmerson mnangagwa swear zimbabwean president friday say hop mnangagwa would steer country successfully transition robert mugabe rule zuma comment first make public since mnangagwa emerge new leader zimbabwe follow military intervention mugabe make talk angolan president joao lourenco south africa capital pretoria lourenco pay state visit south africa previously schedule two leaders attend mnangagwa inauguration harare south africa 's zuma congratulate zimbabwe 's mnangagwa swearing-in