DateUtils.parseDate not fully compliant with RFC 1123

RFC-1123 (http://www.ietf.org/rfc/rfc1123.txt ) says:
There is a strong trend towards the use of numeric timezone
indicators, and implementations SHOULD use numeric timezones
instead of timezone names. However, all implementations MUST
accept either notation. If timezone names are used, they MUST
be exactly as defined in RFC-822.

Ruby on Rails v4 issues cookies with a numeric timezone in the expiry date.
DateUtils.parseDate() is used by HtmlUnit to parse the expiry date of cookies.
This bug means that HtmlUnit does not correctly deal with cookie expiration when talking to a Ruby on Rails application.