PARIS (Reuters) - Societe Generale posted a surprise first-quarter loss on Thursday after hiking provisions for bad loans and suffering a revenue wipeout at its equity trading division amid market volatility caused by the coronavirus.Sales from trading shares slumped 99% to 9 million euros (7.86 million pounds) hit by cancelled dividends, increased hedging costs and a counterparty default, contributing to a 537 milion euro loss at the French lender's corporate and investment bank.The weak..