plugin pubsub schema: allow any data_form schema:

the schema is actually the schema needed for the items, so it should not in pubsub schema namespace.

src/plugins/plugin_exp_pubsub_schema.py

@@ -34,7 +34,6 @@ from collections import Iterable
 import copy
 
 NS_SCHEMA = 'https://salut-a-toi/protocol/schema:0'
-NS_SCHEMA_FORM = 'https://salut-a-toi/protocol/schema#schema:0'
 
 PLUGIN_INFO = {
     C.PI_NAME: "PubSub Schema",
@@ -98,13 +97,11 @@ class PubsubSchema(object):
             schema_elt = next(iq_elt.elements(NS_SCHEMA, 'schema'))
         except StopIteration:
             raise exceptions.DataError('missing <schema> element')
-        schema_form = data_form.findForm(schema_elt, NS_SCHEMA_FORM)
-        if schema_form is None:
+        try:
+            x_elt = next(schema_elt.elements((data_form.NS_X_DATA, 'x')))
+        except StopIteration:
             # there is not schema on this node
             return None
-        # we get again the form because we need all elements/namespaces
-        # while schema_form.toElement while only keep XEP-0004 elements
-        x_elt = next(schema_elt.elements(data_form.NS_X_DATA, 'x'))
         return x_elt
 
     def getSchema(self, client, service, nodeIdentifier):