Chinese Premier Li Keqiang traveled to the epicenter of the country’s dangerous viral outbreak to meet infected patients and front-line health workers, signaling the Beijing leadership’s concern as public frustration rises over how local officials have handled the crisis. The central government website published photos on Monday showing Mr. Li wearing a face mask and swaddled in blue protective gear as he toured medical facilities in Wuhan, a sprawling city in central China where the outbreak began. In one image, Mr….