Playing on NS7 with /usr/bin/clamav-unofficial-sigs.sh I saw that it looks after /etc/clamd.conf when updates are found
Indeed this file is missing
[root@NS7DEV ~]# /usr/bin/clamav-unofficial-sigs.sh
======================================================================
Sanesecurity Database & GPG Signature File Updates
======================================================================
Sanesecurity mirror site used: spamexperts3-mirror.sanesecurity.com 185.95.29.15
Number of files: 52
Number of files transferred: 8
Total file size: 19509836 bytes
Total transferred file size: 3975020 bytes
Literal data: 49451 bytes
Matched data: 3925569 bytes
File list size: 1719
File list generation time: 0.254 seconds
File list transfer time: 0.000 seconds
Total bytes sent: 16417
Total bytes received: 13646
sent 16417 bytes received 13646 bytes 8589.43 bytes/sec
total size is 19509836 speedup is 648.97
Testing updated Sanesecurity database file: blurl.ndb
Sanesecurity GPG Signature tested good on blurl.ndb database
Clamscan reports Sanesecurity blurl.ndb database integrity tested good
Successfully updated Sanesecurity production database file: blurl.ndb
Testing updated Sanesecurity database file: jurlbl.ndb
Sanesecurity GPG Signature tested good on jurlbl.ndb database
Clamscan reports Sanesecurity jurlbl.ndb database integrity tested good
Successfully updated Sanesecurity production database file: jurlbl.ndb
Testing updated Sanesecurity database file: phishtank.ndb
Sanesecurity GPG Signature tested good on phishtank.ndb database
Clamscan reports Sanesecurity phishtank.ndb database integrity tested good
Successfully updated Sanesecurity production database file: phishtank.ndb
Testing updated Sanesecurity database file: porcupine.hsb
Sanesecurity GPG Signature tested good on porcupine.hsb database
Clamscan reports Sanesecurity porcupine.hsb database integrity tested good
Successfully updated Sanesecurity production database file: porcupine.hsb
=================================================
= Update(s) detected, reloaded ClamAV databases =
=================================================
ERROR: Can't parse clamd configuration file /etc/clamd.conf