Avoid hiding HTTPError messages.

slapos/libnetworkcache.py

@@ -162,12 +162,7 @@ class NetworkcacheClient(object):
     file_descriptor = tempfile.NamedTemporaryFile()
     request = urllib2.Request(url=url, data=None,
       headers=self.shadir_header_dict)
-    try:
-      data = urllib2.urlopen(request).read()
-    except urllib2.HTTPError, error:
-      if error.code == httplib.NOT_FOUND:
-        raise DirectoryNotFound('Directory not found at %s' % url)
-      raise
+    data = urllib2.urlopen(request).read()
     # Filtering...
     data_list = json.loads(data)
     if len(data_list) > 1 and not \