Incorrect (depending on your config) check for the validity of $IRONIC_IPMI_INTERFACE and $IRONIC_IPMI_INTERFACE_IP

The "env/metal3/02_configure.sh" script includes the following check to verify that the $IRONIC_IPMI_INTERFACE and $IRONIC_IPMI_INTERFACE_IP variables are coherent.

   if [ "$IRONIC_IPMI_INTERFACE" ]; then
      check_interface_ip $IRONIC_IPMI_INTERFACE $IRONIC_IPMI_INTERFACE_IP
    else
       exit 1
    fi

The problem arises for servers that have the IPMI traffic sharing the same port as another network interface but with separate IP addresses. In that case, the check above will fail if you indicate what the real IPMI IP address is because it will not match the one reported for the network interface in question.

The way around this is to put the network interface IP address as seen by the OS for $IRONIC_IPMI_INTERFACE_IP in user_config.sh, but that is rather unintuitive.

We should consider to either account for this specific configuration, or perhaps get rid of that test altogether (not sure it's that critical?).