dhllabel: They must be encoded with CP1252 and not UTF-8

Fight with rails about the encoding of the label. First we
render, then we encode to the closest we have for CP1252 and
then we need to set response.body as returning the encoded
string will not help us.

app/controllers/admin/shipments_controller_decorator.rb

@@ -2,10 +2,15 @@ Admin::ShipmentsController.class_eval do
   def dhllabel
     load_shipment
     name = '%s_dhllabel.csv' % [@order.number]
-    headers["Content-type"] = "text/plain"
+    headers["Content-type"] = "text/plain; charset=iso-8859-15"
     headers["Cache-Control"] = "no-cache, max-age=0, must-revalidate"
     headers["Pragma"] = "no-cache"
     headers["Expires"] = "Fri, 01 Jan 1990 00:00:00 GMT"
     headers["Content-Disposition"] = "attachment; filename=\"%s\"" % name
+
+    # Try hard to render it as latin1
+    res = render
+    response.charset = 'iso-8859-15'
+    response.body = Iconv.conv('iso-8859-15', 'utf-8', res)
   end
 end