(Reuters) – Struggling electronics retailer RadioShack Corp, which is teetering on the brink of bankruptcy, said John Feray resigned as chief financial officer last week. The company said on Monday it named AlixPartners LLP managing director Holly Etlin as interim CFO. Advisory firm AlixPartners has been helping RadioShack with its turnaround since July 2013. Feray, who joined in January from Dollar General Corp, resigned on Sept. 12 citing personal reasons, RadioShack said in a statement. Etlin also served as RadioShacks interim CFO between July 2013 and February. …