* http.scm (http:message-status-ok?): Use http:message-status-code,
        not non-existant http:status-code.

The problem can be seen with for instance,

	(use-modules (www url)
	             (www http))
	(http:message-status-ok?
         (http:get (url:parse "http://www.zip.com.au")))

giving an error

	ERROR: Unbound variable: http:status-code