fix(platform): check cni config file

[Huimintai]

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespace from that line:

/kind api-change
/kind bug
/kind cleanup
/kind deprecation
/kind design
/kind documentation
/kind failing-test
/kind feature
/kind flake

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

[leoryu]

What dose the label mean?

[Huimintai]

What dose the label mean?

Label indicates for individual DirEmptyCheck. If not known, will return this string [ERROR DirEmptyCheck--etc-cni-net.d].
We use Name function in RunChecks function please see details on this function:

func RunChecks(checks []Checker) error {
	var errsBuffer bytes.Buffer

	for _, c := range checks {
		name := c.Name()
		warnings, errs := c.Check()

		for _, w := range warnings {
			errsBuffer.WriteString(fmt.Sprintf("\t[WARNING %s]: %v\n", name, w))
		}
		for _, i := range errs {
			errsBuffer.WriteString(fmt.Sprintf("\t[ERROR %s]: %v\n", name, i.Error()))
		}
	}
	if errsBuffer.Len() > 0 {
		return &Error{Msg: errsBuffer.String()}
	}
	return nil
}