Log Message:
Update to Dovecot 1.1beta13.

Changes since beta12:

 - Half of LDAP code was rewritten to fix reconnect/queuing problems. I did
   test that the new code works with and without auth binds, but be careful.
 - \Recent flags should finally work correctly with maildir.
 - last_used field wasn't updated for cache fields that were permanently
   cached. This caused them to be dropped after a month.

TODO for RC1:

 - When pipelining commands, do only one sync after all of them. Besides
   improving performance, this fixes some rare problems when multiple commands
   are running simultaneously.
 - SEARCH/SORT: Replace invalid input with unicode "replacement character"
   instead of just skipping it.
 - Squat: Handle expunges. NFS support.
 - Fix Lucene support.