Import imaplib2 instead of imaplib

imaplib2 has slightly different semantics than standard imaplib, so
this patch will break the build, but I thought it was helpful to have it as
a separate commit.

Signed-off-by: Ethan Glasser-Camp <ethan@betacantrips.com>
Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>

offlineimap/init.py

@@ -19,7 +19,7 @@
 import os
 import sys
 import threading
-import imaplib
+import offlineimap.imaplib2 as imaplib
 import signal
 import socket
 import logging