Traceback if a security labels lacks displaymarking.
Bug description
Traceback (most recent call last):
File "src/common/xmpp/idlequeue.py", line 533, in _process_events
return IdleQueue._process_events(self, fd, flags)
File "src/common/xmpp/idlequeue.py", line 394, in _process_events
obj.pollin()
File "src/common/xmpp/transports_nb.py", line 414, in pollin
self._do_receive()
File "src/common/xmpp/transports_nb.py", line 600, in _do_receive
self._on_receive(received)
File "src/common/xmpp/transports_nb.py", line 614, in _on_receive
self.on_receive(data)
File "src/common/xmpp/dispatcher_nb.py", line 453, in dispatch
handler['func'](session, stanza)
File "src/common/connection_handlers.py", line 1413, in _SecLabelCB
label = item.getTag('displaymarking').getData()
AttributeError: 'NoneType' object has no attribute 'getData'
Steps to reproduce
Catalog with an label without \<displaymarking/>