Make IDLE mode to work again

Refactoring in commit 6cbd2498 touched wrong class's "idle" call.

Found-by: Tomasz Żok <tomasz.zok@gmail.com>
Signed-off-by: Eygene Ryabinkin <rea@codelabs.ru>

Changelog.rst

@@ -5,6 +5,14 @@ ChangeLog
 :website: http://offlineimap.org
 
 
+OfflineIMAP v6.5.6 (2014-05-14)
+===============================
+
+* Fix IDLE mode regression (it didn't worked) introduced
+  after v6.5.5 (pointy hat goes to Eygene Ryabinkin, kudos --
+  to Tomasz Żok)
+
+
 OfflineIMAP v6.5.6-RC1 (2014-05-14)
 ===================================
 

offlineimap/imapserver.py

@@ -703,7 +703,7 @@ class IdleThread(object):
                 else:
                     success = True
             if "IDLE" in imapobj.capabilities:
-                imapobj.__idle(callback=callback)
+                imapobj.idle(callback=callback)
             else:
                 self.ui.warn("IMAP IDLE not supported on server '%s'."
                     "Sleep until next refresh cycle." % imapobj.identifier)