elf signature for clamav

[Benny Pedersen]

# cat local_elf.ndb from /var/lib/clamav (databasedir in clamd)
Sanesecurity.ELF.1:6:0:7F454C46

took me 5 mins to make :)

thanks to KAM on this its very simple, i like feed back from mimedefang 
and amavisd users