Description of problem:

baremetal-runtimecfg (haproxy-monitor) sets/removes firewall rule that redirects API traffic to LB, it runs [1] to verify kube-api health status via the LB. 
 
It uses IPv4 localhost address (127.0.0.1)to communicate with the local LB, it should use 'localhost' to cover both IPv4 and IPv6 cases.

Additionally, based on [2] we should check 'readyz' endpoint and not 'healthz'  


[1] https://github.com/openshift/baremetal-runtimecfg/blob/master/pkg/utils/utils.go#L86
[2] https://github.com/openshift/installer/blob/master/docs/dev/kube-apiserver-health-check.md#load-balancer-health-check-probe