Log Message:
Update net/couriertcpd to 0.56.0.  Changes from version 0.53.2 include:

+ Remove BDB_LIB workaround which should already be handled by the wrapper
  scripts and db1.builtin.mk.
+ Remove unnecessary patch-aa and patch-ab.

* Setting protocol to SSL3 will now disable SSL2.
* Send a dummy EHLO before STARTTLS (gmail wants it).
* Allow setting the max # of connections on a per-IP address basis.