python: idl: Set cond_changed to true if condition change requested.

cond_changed set to true if _req_cond (requested condition change)
is not none.  This can avoid falling into an endless poll loop,
because cond_changed is true will trigger immediate_wake().

Fixes: 46d44cf3be ("python: idl: Add monitor_cond_since support.")
Signed-off-by: Wentao Jia <wentao.jia@easystack.cn>
Acked-by: Dumitru Ceara <dceara@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>

python/ovs/db/idl.py

@@ -366,7 +366,7 @@ class Idl(object):
             else:
                 if table.condition.reset():
                     self.last_id = str(uuid.UUID(int=0))
-                self.cond_changed = True
+                    self.cond_changed = True
 
     def restart_fsm(self):
         # Resync data DB table conditions to avoid missing updated due to