Log Message:
Update to 2.5.1.

This release adds checking of a number of archive members to improve
protection from runaway dearchivers.

It fixes SQL quarantining of mail with a null sender, and recognizes
PostgreSQL error S8006.

Parsing of invalid header has been improved.

Calling 'finish' on a SA message object was added.

A nonstandard SMTP status code 254 is no longer used, and enforcing
of option 8BITMIME is avoid even on 8-bit contents.

Checking of eval status was improved to recognize additional failure
modes.

Disabling of MIME decoding and invoking of a file(1) utility has been
made possible. An AV entry for ArcaVir was added.