keys in /var/keys are not in the `keys` group

[Profpatsch]

# l /var/keys
total 24K
drwxr-x---  2 root keys 4.0K Jun 19 13:14 .
drwxr-xr-x 10 root root 4.0K Jun 19 13:04 ..
-rw-r-----  1 root root 1.9K Jun 19 13:14 certificate_pem

/var/keys itself is root:keys, but the keys in it are root:root and readable only by user and group, so they are unreadable by the keys group.

[Profpatsch]

Fixed by #32