Medical staff members take part in a Ebola virus preventive drill at Ditan Hospital in Beijing, October 30, 2014. LONDON (Reuters) - (The story was corrected in the first and fourth paragraphs of Oct. 28 story to show Aon is based in Britain, and not the United States) British insurance broker Aon has launched Ebola liability cover for hospitals and other health care institutions, the company said on Tuesday.The Ebola...