Photo Illustration by Luis G. Rendon/The Daily Beast/GettyElon Musk insists the emerald mines he once boasted about never existed.But his father, Errol Musk, was only too happy to tell The Daily Beast tales of covert arrivals, killer crocodiles and a litany of exotic diseases from when he struck it big in the gemfields of Zambia 40 years ago.He says he survived his stints in the bush on a diet of bullrush maize meal and dried kapenta, a freshwater sardine found in Lake Tanganyika.“Elon came with