jingle XEP-0166: fixed session creation on non session-initiate actions

src/plugins/plugin_xep_0166.py

@@ -411,6 +411,11 @@ class XEP_0166(object):
         try:
             session = client.jingle_sessions[sid]
         except KeyError:
+            if action != XEP_0166.A_SESSION_INITIATE:
+                log.warning(u"Received request for an unknown session id: {}".format(sid))
+                self.sendError('not-acceptable', None, request, profile=profile)
+                return
+
             session = client.jingle_sessions[sid] = {'id': sid,
                                                      'state': STATE_PENDING,
                                                      'initiator': peer_jid,