Use email string.

src/mailman.scm

@@ -152,7 +152,7 @@
 	  (mailman-send/recv
 	   "add_members"
 	   (list "-r" "-" listname)
-	   (sprintf "<<<\"~A\"" email))))
+	   email)))
      (let loop ((lines result))
        (when (not (null? lines))
 	 (print " | " (car lines))