go lint/vet/misspell cleanup (#1105)

This fix address several issues related to golint/vet/misspell.
Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

plugin/dnstap/out/socket.go

@@ -78,9 +78,5 @@ func (s *Socket) Close() error {
 	if err := s.enc.Flush(); err != nil {
 		return fmt.Errorf("flush: %s", err)
 	}
-	if err := s.enc.Close(); err != nil {
-		return err
-	}
-
-	return nil
+	return s.enc.Close()
 }

plugin/dnstap/out/tcp_test.go

@@ -9,11 +9,9 @@ func sendOneTCP(tcp *TCP) error {
 	if _, err := tcp.Write([]byte("frame")); err != nil {
 		return err
 	}
-	if err := tcp.Flush(); err != nil {
-		return err
-	}
-	return nil
+	return tcp.Flush()
 }
+
 func TestTCP(t *testing.T) {
 	tcp := NewTCP("localhost:14000")
 

plugin/file/file.go

@@ -113,7 +113,7 @@ type serialErr struct {
 }
 
 func (s *serialErr) Error() string {
-	return fmt.Sprintf("%s for origin %s in file %s, with serial %d", s.err, s.zone, s.serial)
+	return fmt.Sprintf("%s for origin %s in file %s, with serial %d", s.err, s.origin, s.zone, s.serial)
 }
 
 // Parse parses the zone in filename and returns a new Zone or an error.

plugin/pkg/dnstest/recorder.go

@@ -21,7 +21,7 @@ type Recorder struct {
 	Start time.Time
 }
 
-// New makes and returns a new Recorder,
+// NewRecorder makes and returns a new Recorder,
 // which captures the DNS rcode from the ResponseWriter
 // and also the length of the response message written through it.
 func NewRecorder(w dns.ResponseWriter) *Recorder {

plugin/rewrite/rewrite.go

@@ -94,7 +94,7 @@ func newRule(args ...string) (Rule, error) {
 		expectNumArgs = len(args) - 1
 		startArg = 2
 	default:
-		// for backward compability
+		// for backward compatibility
 		ruleType = arg0
 		expectNumArgs = len(args)
 		startArg = 1