Remove the dead code path for passing incoming message data through the mfa.
It is not going to be done that way.
Internal update for the upcoming filter infrastructure:
- use log.c
- pass filter name to filter process
- various API improvements
Allow the construction of filterchains as a sequence of individual filters
and or other filterchains.
missing include
include the right header...
More changes in the filter framework/API.
Add code to eventually pass the message content through the mfa.
The mfa will get the output message fd from the queue, setup a filter
chain for the content, and send the filter input socket to the smtp
process.

This is not plugged for now.
add missing header and fix format string