dovecot: add latest upstream fixes and improvements for dovecot 2.2.1

Note:

The patch now includes all fixes and improvements for dovecot 2.2.1 from the
dovecot 2.2 branch up to http://hg.dovecot.org/dovecot-2.2/rev/df20af39dc51.
dovecot: add latest upstream fixes and improvements for dovecot 2.2.1

Note:

The patch now includes all fixes and improvements for dovecot 2.2.1 from the
dovecot 2.2 branch up to http://hg.dovecot.org/dovecot-2.2/rev/1d6f42853492.
dovecot: fix upstream patchset by removing non-applying patch to auth-dict.conf.ext example config

auth-dict.conf.ext cannot be patched because it was not distributed within the
release tarball!

The issue has been reported and a patch sent upstream:

http://dovecot.org/list/dovecot/2013-May/090432.html
dovecot-antispam: Updated (2.2-0319240072d8 -> 2.2-5ebc6aae4d7c)