Undesired ban of text mail

[Damian]

>> What's your (and other people's) advice?
> 
> You can place lines 8-13 from Savvas Karagiannidis' link in /etc/magic.

I realized that this won't help. The new definition in /etc/magic will not match (which is the purpose of the upstream change), so 
file will continue and use the definition from the package.

Instead you would need to place the old definition [1] in /etc/magic and change the "executable" message to something else, so 
that the modified test matches but returns the modified result.

Another possibility is to change the mapping for "PARIX executable" inside amavis via @map_full_type_to_short_type_maps.

[1] https://github.com/file/file/commit/773a48a118b7647f6e7555c726f0b4c2a41cb2d0