Fix condition check to show a warning

Author: ales-erjavec

Orange/canvas/scheme/signalmanager.py

@@ -301,7 +301,7 @@ def process_queued(self, max_nodes=None):
         Take one node node from the pending input queue and deliver
         all scheduled signals.
         """
-        if max_nodes is not None or max_nodes != 1:
+        if not (max_nodes is None or max_nodes == 1):
             warnings.warn(
                 "`max_nodes` is deprecated and unused (will always equal 1)",
                 DeprecationWarning, stacklevel=2)