Extraneous spacing in plugin output from errors and thresholds sections

[atc0005]

Here we emit two leading nagios.CheckOutputEOL separators:

go-nagios/sections.go

Lines 47 to 54 in 06615b3

	fmt.Fprintf(w,
	"%s%s**%s**%s%s",
	CheckOutputEOL,
	CheckOutputEOL,
	p.getErrorsLabelText(),
	CheckOutputEOL,
	CheckOutputEOL,
	)

This should probably be a single separator.

Here we opt to emit the separator if sections are not displayed:

go-nagios/sections.go

Lines 122 to 140 in 06615b3

	// Hide section header/label if threshold and error values were not
	// specified by client code or if client code opted to explicitly hide
	// those sections; there is no need to use a header to separate the
	// LongServiceOutput from those sections if they are not displayed.
	//
	// If we hide the section header, we still provide some padding to
	// prevent the LongServiceOutput from running up against the
	// ServiceOutput content.
	switch {
	case !p.isThresholdsSectionHidden() || !p.isErrorsHidden():
	fmt.Fprintf(w,
	"%s**%s**%s",
	CheckOutputEOL,
	p.getDetailedInfoLabelText(),
	CheckOutputEOL,
	)
	default:
	fmt.Fprint(w, CheckOutputEOL)
	}

This default separator is likely not needed.