Britain's FTSE 100 index is seen opening up 1 point at 7,426 on Wednesday, according to financial bookmakers. * SHELL: Royal Dutch Shell Plc is about halfway through a planned overhaul of the gasoline-producing Residual Catalytic Cracking Unit (RCCU) at its 218,200 barrel-per-day (bpd) Norco, Louisiana refinery, said sources familiar with plant operations. * INDIVIOR: The U.S. Justice Department announced on Tuesday the indictment of Indivior Plc and a s