TTYUI: Fix missing "time" import

commit f2a94af5 introduced the use of time.sleep in ui/TTY.py without
importing it. This caused a regression in 6.5.2, crashing OfflineIMap
when in refresh mode.

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>

offlineimap/ui/TTY.py

@@ -17,6 +17,7 @@
 
 import logging
 import sys
+import time
 from getpass import getpass
 from offlineimap import banner
 from offlineimap.ui.UIBase import UIBase