Add needed comments for `golint` cleanup. (#334)

This fix adds several needed comments in
`middleware/kubernetes/nametemplate/nametemplate.go`
to clean up golint output.

There are still 3 places that needs proper docs:
```
middleware/kubernetes/nametemplate/nametemplate.go:64:1: comment on exported type Template should be of the form "Template ..." (with optional leading article)
middleware/kubernetes/nametemplate/nametemplate.go:72:1: comment on exported method Template.SetTemplate should be of the form "SetTemplate ..."
middleware/kubernetes/nametemplate/nametemplate.go:188:1: comment on exported type NameValues should be of the form "NameValues ..." (with optional leading article)
```

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

1 files changed, 10 insertions, 6 deletions

diff --git a/middleware/kubernetes/nametemplate/nametemplate.go b/middleware/kubernetes/nametemplate/nametemplate.go
index e879006cc..1ddfea1da 100644
--- a/middleware/kubernetes/nametemplate/nametemplate.go
+++ b/middleware/kubernetes/nametemplate/nametemplate.go
@@ -69,7 +69,7 @@ type Template struct {
 	Element map[string]int
 }
 
-// TODO: docs
+// TODO(infoblox): docs
 func (t *Template) SetTemplate(s string) error {
 	var err error
 
@@ -107,24 +107,28 @@ func (t *Template) SetTemplate(s string) error {
 //		 to treat the query string segments as a reverse stack and
 //       step down the stack to find the right element.
 
+// ZoneFromSegmentArray returns the zone string from the segments.
 func (t *Template) ZoneFromSegmentArray(segments []string) string {
 	index, ok := t.Element["zone"]
 	if !ok {
 		return ""
 	}
-	return strings.Join(segments[index:len(segments)], ".")
+	return strings.Join(segments[index:], ".")
 }
 
+// NamespaceFromSegmentArray returns the namespace string from the segments.
 func (t *Template) NamespaceFromSegmentArray(segments []string) string {
-	return t.SymbolFromSegmentArray("namespace", segments)
+	return t.symbolFromSegmentArray("namespace", segments)
 }
 
+// ServiceFromSegmentArray returns the service string from the segments.
 func (t *Template) ServiceFromSegmentArray(segments []string) string {
-	return t.SymbolFromSegmentArray("service", segments)
+	return t.symbolFromSegmentArray("service", segments)
 }
 
+// TypeFromSegmentArray returns the type string from the segments.
 func (t *Template) TypeFromSegmentArray(segments []string) string {
-	typeSegment := t.SymbolFromSegmentArray("type", segments)
+	typeSegment := t.symbolFromSegmentArray("type", segments)
 
 	// Limit type to known types symbols
 	if dns_strings.StringInSlice(typeSegment, types) {
@@ -134,7 +138,7 @@ func (t *Template) TypeFromSegmentArray(segments []string) string {
 	return typeSegment
 }
 
-func (t *Template) SymbolFromSegmentArray(symbol string, segments []string) string {
+func (t *Template) symbolFromSegmentArray(symbol string, segments []string) string {
 	index, ok := t.Element[symbol]
 	if !ok {
 		return ""