Log Message:
Update mimedefang to 2.61.

includes patch to work with clamav 0.90 and newer.

Changes since 2.59:

* SECURITY FIX: Versions 2.59 and 2.60 contained a programming error
  that could lead to a buffer overflow. This is definitely
  exploitable as a denial-of-service attack, and potentially may
  allow arbitrary code execution. The bug is fixed in 2.61.
* If a message is going to end up being rejected,
  discarded or tempfailed, we don't bother carrying out requests
  to add/delete/modify headers or recipients, change the message
  body, etc.
* mimedefang.c: Fix filter registration so MIMEDefang works
  correctly against libmilter from Sendmail 8.14

Changes since 2.58:

* A new "watch-multiple-mimedefangs.tcl" tool that lets you keep an eye
  on a cluster of MIMEDefang scanners.
* Fixes to the build scripts that should eliminate build problems on
  Intel/AMD 64-bit architectures.
* mimedefang generates the COMMANDS file more safely and more efficiently.
* Various other minor improvements and bug-fixes.