Allows to specify a domain when deleting a cookie.

When a cookie has been set with a given domain (i.e. domain="example.com"), subsequent attempts to delete it will be ignored by the browser if the same domain is not provided.

So a 'domain' parameter is added to the 'delete_cookie' method in order to be able to delete those cookies.

src/wsapi/response.lua

@@ -87,8 +87,8 @@ function methods:set_cookie(name, value)
   end
 end
 
-function methods:delete_cookie(name, path)
-  self:set_cookie(name, { value =  "xxx", expires = 1, path = path })
+function methods:delete_cookie(name, path, domain)
+  self:set_cookie(name, { value =  "xxx", expires = 1, path = path, domain = domain })
 end
 
 function methods:redirect(url)