FRANKFURT (Reuters) - Top executives from General Motors who sit on the board of loss-making European brand Opel are meeting on Wednesday to approve the first closure of a German car factory in decades. As part of a comprehensive turnaround plan, Opel will end producing Zafira MPVs at its 50-year old Bochum plant by the end of next year, a move that has triggered a rare and public split within union ranks following months of tough negotiations. ...