Don't assume res._header exist

SpaceK33z · SpaceK33z · commit 294fd4e78524 · 2016-09-19T23:24:51.000+02:00
`res._header` is an internal implementation detail. Hence, some implementations of the http server do not set this. [node-spdy](https://github.com/indutny/node-spdy) is an example.
diff --git a/src/webjs.coffee b/src/webjs.coffee
@@ -120,7 +120,7 @@ exports.GenericApp = class GenericApp
     log_request: (req, res, data) ->
         td = (new Date()) - req.start_date
         @log('info', req.method + ' ' + req.url + ' ' + td + 'ms ' +
-                (if res.finished then res._header.split('\r')[0].split(' ')[1] \
+                (if res.finished and res._header then res._header.split('\r')[0].split(' ')[1] \
                                   else '(unfinished)'))
         return data
 
