Open vSwitch log files not readable by fluentd

Open vSwitch log files (/var/log/kolla/openvswitch/ovsdb-server.log and /var/log/kolla/openvswitch/ovs-vswitchd.log) are not readable by fluentd.

This was seen while adding a check in CI for readability of these files via the following command:

$ docker exec -it fluentd bash
find /var/log/kolla/ -type f | while read f; do test -r $f || echo "Cannot read $f"; done

Generally there are a few ways in which access is provided to log file for fluentd:

1. Set log file ownership to $USER:kolla, permissions to 0640.
2. Set log file ownership to $USER:$USER, permissions to 0644.
3. MariaDB is a special case, and uses 0640 with the fluentd user added to the mysql group.

Of these, 1. seems the most secure.