core (xmpp): fixed URI correction while parsing messages:

A double "==" was used instead of a single one. As a result URI was never fixed and some
elements could be missed (like body), and then the message discarded.
Should fix 294 (to be confirmed).

fix 294

sat/core/xmpp.py

@@ -971,7 +971,7 @@ class SatMessageProtocol(xmppim.MessageProtocol):
             message_elt.defaultUri = message_elt.uri = C.NS_CLIENT
             for c in message_elt.elements():
                 if c.uri is None:
-                    c.uri == C.NS_CLIENT
+                    c.uri = C.NS_CLIENT
         elif message_elt.uri != C.NS_CLIENT:
             log.warning(_(
                 u"received <message> with a wrong namespace: {xml}"