Zong Qinghou, a self-made beverage entrepreneur who was once the richest person in China, died on Sunday. His death was announced by his company, Wahaha Group, which said that Mr. Zong had died from an unspecified illness and gave his age as 79. The company statement provided no further details. Mr. Zong’s rags-to-riches story had made him prominent in China even before a public feud with his foreign business partner considerably raised his profile — and his wealth. He founded a beverage company in the 1980s, and in the 1990s,…