Misc url-cookie tidy-up.

Misc url-cookie tidy-up.

* lisp/url/url-cookie.el: Don't require cl when compiling.
(url-cookie-clean-up, url-cookie-generate-header-lines): Use dolist.
(url-cookie-parse-file, url-cookie-store, url-cookie-retrieve)
(url-cookie-handle-set-cookie): Simplify.