Info and warnings messing up the JSON output

[lizrice]

kube-bench currently issues info output about the config file it's using, as well as warnings about config files that can't be found, or when it doesn't have executables in its path to check version number. These warnings need to be omitted when the output format is JSON.

[WARN] kube-apiserver: command not found on path - version check skipped
[WARN] kube-scheduler: command not found on path - version check skipped
[WARN] kube-controller-manager: command not found on path - version check skipped
[WARN] config file /etc/kubernetes/apiserver does not exist
[WARN] config file /etc/kubernetes/scheduler does not exist
[WARN] config file /etc/kubernetes/controller-manager does not exist
[WARN] config file /etc/kubernetes/config does not exist
[WARN] config file /etc/etcd/etcd.conf does not exist
[WARN] config file /etc/sysconfig/flanneld does not exist
{"ID":"1","Text":"Master Node Security Configuration","Type":"master","Groups":[{"ID":"1.1","Text":"API Server","Checks":[{"id":"1.1.1","Text":"Ensure that the --allow-privileged argument is set to false (Scored)","Remediation":"Edit the /etc/kubernetes/config file on the master node and set the KUBE_ALLOW_PRIV parameter to \"--allow-privileged=false\"","State":"FAIL"},{"id":"1.1.2","Text":"Ensure that the --anonymous-auth argument is set to false (Scored)","Remediation":"Edit the /etc/kubernetes/apiserver file on the master node and set the KUBE_API_ARGS parameter to \"--anonymous-auth=false\"","State":"FAIL"},{"id":"1.1.3","Text":"Ensure that the --basic-auth-file argument is not set (Scored)","Remediation":"Follow the documentation and configure alternate mechanisms for authentication. Then, edit the /etc/kubernetes/apiserver file on the master node and remove the \"--basic-auth-file=\u003cfilename\u003e\" argument from the KUBE_API_ARGS parameter.","State":"PASS"},{"id":"1.1.4","Text":"Ensure that the --insecure-allow-any-token argument is not set (Scored)","Remediation":"Edit the /etc/kubernetes/apiserver file on the master node and remove the --insecure-allow-any-token argument from the KUBE_API_ARGS parameter.","State":"PASS"},{"id":"1.1.5","Text":"Ensure that the --kubelet-https argument is set to true (Scored)","Remediation":"Edit the /etc/kubernetes/apiserver file on the master node and remove the --kubelet-https argument from the KUBE_API_ARGS parameter.","State":"FAIL"},{"id":"1.1.6","Text":"Ensure that the --insecure-bind-address argum...```