A Southern California couple bought a small Napa winery on Monday, besting other would-be buyers by agreeing to close within 10 days and paying all cash for the $4.7 million property on Silverado Trail near Calistoga.Monday’s deal is the latest indication that so-called lifestyle buyers, who are more focused on creating a hobby business in Wine Country than turning a quick or substantial profit, might be returning to the market after a two-year absence. “We had the winery on the market for a year, and nothing,” said John Bergman, a Napa real estate agent specializing in wineries and vineyards who represented both the buyer and seller. “And then all of a sudden we had six offers.”