A US$1 billion fortune left behind by a 19th century Muslim shipping magnate who built a guest house for pilgrims to Mecca is being fought over by two feuding families in India.The money has been lying in a Saudi Arabian coffer for decades due to the inability of both the Saudi and Indian governments to adjudicate which of the two families, who live within a few miles of each other in Kannur, Kerala, has the rightful claim.At the heart of the dispute between the Keyi family, who number around 1…