Signature can be empty.

slapos/libnetworkcache/__init__.py

@@ -114,7 +114,7 @@ class NetworkcacheClient(object):
 
       signature = kw.get('signature', None)
       if signature is None:
-        signature = "SIGNATURE"
+        signature = ''
       data = [kw, signature]
 
       shadir_connection = httplib.HTTPConnection(self.shadir_host)