debug message that's really an error: replica (ITS#147)

[ahu@vvtp.tn.tudelft.nl]

I had some trouble today with slapd & slurpd. It turns out that a replica
line in the wrong place is silently ignored and that invalid replica logs
are being written as a result.

Right now slapd only issues a debugging notice if it notices this error, I
think it should be a full blown error.

After the warning, it runs, but generates replica logs without a replica:
header, which are skipped by slurpd.

Futhermore, I was wondering how the replica 'knows' how to refer updates
back to the master. Should I include a referral for this? 

Thanks, and good luck everybody, LDAP is fun!