Pass correct arguments to six.reraise

six.reraise input arguments are:
  six.reraise(exc_type, exc_value, exc_traceback=None)

This information is provided by sys.exc_info() and stored
in self.communication_error.

Trivial-Fix

Change-Id: Ibe68d8e36ca424da61a0a9eea20e622440c79464

oslo_privsep/daemon.py

@@ -504,7 +504,7 @@ class Daemon(object):
                 if error[1].errno == errno.EPIPE:
                     # Write stream closed, exit loop
                     break
-                six.reraise(error)
+                six.reraise(*error)
 
             # Submit the command for execution
             future = self.thread_pool.submit(self._process_cmd, msgid, *msg)