Bug#321462: exim4-config: Issue a warning if CFILEMODE allows world-read and config file has any hide options

[Dave]

This is a quicky that I've barely tested (and used constant directory 
paths/names in), but this should be along those lines (except for the 
case of no configuration files, which I presume is an illegal state)

#in bash:
cd /etc/exim4
let MODE=`find .. -printf '0%m&'|sed 's/&$//'`\&0$CFILEMODE
chmod `printf %o`$MODE /var/lib/exim4/config.autogenerated