By Kate Abnett BRUSSELS (Reuters) -The European Union must avoid locking itself into years of dependence on fossil fuels as it races to replace Russian oil and gas with supplies from other countries, 11 former EU policy chiefs have said in a letter to the bloc’s current leadership. The European Commission will this month unveil plans to end Europe’s reliance on Russian energy, which are expected to expand renewable energy faster while encouraging the urgent replacement of Russian gas with alternative supplies. “Simply diversifying the import of fossil fuels will only serve to maintain EU energ…