fix the panic when "ps -a" with dead containers

Signed-off-by: Shijiang Wei <mountkin@gmail.com>

api/handlers.go

@@ -282,9 +282,13 @@ func getContainersJSON(c *context, w http.ResponseWriter, r *http.Request) {
 		}
 
 		// Apply filters.
+		if len(container.Names) > 0 {
 			if !filters.Match("name", strings.TrimPrefix(container.Names[0], "/")) {
 				continue
 			}
+		} else if len(filters["name"]) > 0 {
+			continue
+		}
 		if !filters.Match("id", container.Id) {
 			continue
 		}