Comment 3 for bug 1778812

Adding "r" as mentioned is enough to fix freshclam's own logrotation:
-rw-r----- 1 clamav clamav 1.5K Jul 9 19:21 freshclam.log
-rw-r----- 1 clamav adm 3.6K Jul 9 19:20 freshclam.log-20180709_192102
-rw-r----- 1 clamav adm 3.2K Jul 9 19:15 freshclam.log.1

The .1 one was via logrotate -f, whereas the -20180709 one was after I adjusted freshclam.conf to rotate aggressively on 3kbytes.