Logrotate failure

[Tony van der Hoff <tony@vanderhoff.org>]

Since installing Jessie from scratch on this laptop, I'm getting a
nightly error message from logrotate:

/etc/cron.daily/logrotate:
error: error running shared postrotate script for '/var/log/mysql.log
/var/log/mysql/mysql.log /var/log/mysql/mysql-slow.log
/var/log/mysql/error.log '
run-parts: /etc/cron.daily/logrotate exited with return code 1

/etc/logrotate.d/mysql-server is unchanged from the packaged version:

# - I put everything in one block and added sharedscripts, so that mysql
gets
#   flush-logs'd only once.
#   Else the binary logs would automatically increase by n times every day.
# - The error log is obsolete, messages go to syslog now.
/var/log/mysql.log /var/log/mysql/mysql.log
/var/log/mysql/mysql-slow.log /var/log/mysql/error.log {
	daily
	rotate 7
	missingok
	create 640 mysql adm
	compress
	sharedscripts
	postrotate
		test -x /usr/bin/mysqladmin || exit 0

		# If this fails, check debian.conf!
		MYADMIN="/usr/bin/mysqladmin --defaults-file=/etc/mysql/debian.cnf"
		if [ -z "`$MYADMIN ping 2>/dev/null`" ]; then
		  # Really no mysqld or rather a missing debian-sys-maint user?
		  # If this occurs and is not a error please report a bug.
		  if ps cax | grep -q mysqld; then
 		    exit 1
		  fi
		else
		  $MYADMIN flush-logs
		fi
	endscript
}

I actually installed mariadb, not mysql, not sure whether that matters.

Any suggestions as to what's wrong, please?

-- 
Tony van der Hoff        | mailto:tony@vanderhoff.org
Buckinghamshire, England |