A man who operated two businesses that sold office supplies to the federal government has been convicted by a federal jury of giving illegal gifts to federal employees who did business with his companies. Ivan Greenhut, 57, of Tarzana, was convicted late yesterday afternoon in United States District Court of one count of conspiring to give gifts to federal officials who purchased products from Greenhut’s companies and one count of giving a gift to a public official, specifically a United States Army employee who purchased products from Greenhut’s companies.