Verify Permissions on the OVNKubernetes DB files

Description

To properly set the permissions of /var/lib/ovn/etc/*.db, run the command:

$ sudo chmod 0640 /var/lib/ovn/etc/*.db

Rationale

CNI (Container Network Interface) files consist of a specification and libraries for writing plugins to configure network interfaces in Linux containers, along with a number of supported plugins. Allowing writeable access to the files could allow an attacker to modify the networking configuration potentially adding a rogue network connection.