A court in Vietnam has convicted 46 former bankers and businessmen of corruption on Monday over a multi-million-dollar lending scam spearheaded by the once-powerful chairman of Vietnam's Construction Bank.It is the latest in a series of major banking trials aimed at cleaning up the opaque sector long plagued by bad debts, corruption and nepotism.Vietnam's communist leaders have vowed to target the banking business as they wage a sweeping anti-graft campaign which observers say is un