jp (base): new own_jid host attribute:

this attribute is None by default and must be filled at runtime if needed by a command.

sat_frontends/jp/base.py

@@ -192,6 +192,8 @@ class Jp(object):
             self._outputs[type_] = OrderedDict()
         self.default_output = {}
 
+        self.own_jid = None  # must be filled at runtime if needed
+
     def _bridgeEb(self, failure):
         if isinstance(failure, exceptions.BridgeExceptionNoService):
             print(_(u"Can't connect to SàT backend, are you sure it's launched ?"))