accounts: remove unused imaplibutil import

Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>

offlineimap/accounts.py

@@ -21,7 +21,7 @@ import time
 from sys import exc_info
 import traceback
 
-from offlineimap import mbnames, CustomConfig, OfflineImapError, imaplibutil
+from offlineimap import mbnames, CustomConfig, OfflineImapError
 from offlineimap import globals
 from offlineimap.repository import Repository
 from offlineimap.ui import getglobalui