make sqlite status cache the default

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

offlineimap.conf

@@ -302,26 +302,16 @@ remoterepository = RemoteExample
 #
 # This example plays a sound file of your chosing when new mail arrives.
 #
-#newmail_hook = lambda: os.system("cvlc --play-and-stop --play-and-exit /path/to/sound/file.mp3" +
-#				 " > /dev/null 2>&1")
+#newmail_hook = lambda: os.system(
+#"cvlc --play-and-stop --play-and-exit /path/to/sound/file.mp3 > /dev/null 2>&1")
 
 
 # This option stands in the [Account Test] section.
 #
-# OfflineImap caches the state of the synchronisation to e.g. be able to
-# determine if a mail has been added or deleted on either side.
+# The historical backend is 'plain' which writes out the state in plain text
+# files. See manual.
 #
-# The default and historical backend is 'plain' which writes out the
-# state in plain text files. On Repositories with large numbers of
-# mails, the performance might not be optimal, as we write out the
-# complete file for each change.  Another new backend 'sqlite' is
-# available which stores the status in sqlite databases.
-#
-# If you switch the backend, you may want to delete the old cache
-# directory in ~/.offlineimap/Account-<account>/LocalStatus manually
-# once you are sure that things work.
-#
-#status_backend = plain
+#status_backend = sqlite
 
 
 # This option stands in the [Account Test] section.