Cleanup in go vet and misspell (#996)

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

middleware/federation/federation.go

@@ -118,7 +118,7 @@ func (f *Federation) Name() string { return "federation" }
 // label is always the 2nd to last once the zone is chopped of. For instance
 // "nginx.mynamespace.myfederation.svc.example.com" has "myfederation" as the federation label.
 // IsNameFederation returns a new qname with the federation label and the label itself or two
-// emtpy strings if there wasn't a hit.
+// empty strings if there wasn't a hit.
 func (f *Federation) isNameFederation(name, zone string) (string, string) {
 	base, _ := dnsutil.TrimZone(name, zone)
 

middleware/kubernetes/parse.go

@@ -74,7 +74,7 @@ func parseRequest(state request.Request) (r recordRequest, err error) {
 		return r, nil
 	}
 
-	// Becuase of ambiquity we check the labels left: 1: an endpoint. 2: port and protocol.
+	// Because of ambiquity we check the labels left: 1: an endpoint. 2: port and protocol.
 	// Anything else is a query that is too long to answer and can safely be delegated to return an nxdomain.
 	switch last {
 

middleware/rewrite/edns0.go

@@ -234,11 +234,11 @@ func (rule *edns0VariableRule) ruleData(w dns.ResponseWriter, r *dns.Msg) ([]byt
 		return []byte(req.Proto()), nil
 
 	case serverIP:
-		serverIp, _, err := net.SplitHostPort(w.LocalAddr().String())
+		ip, _, err := net.SplitHostPort(w.LocalAddr().String())
 		if err != nil {
-			serverIp = w.RemoteAddr().String()
+			ip = w.RemoteAddr().String()
 		}
-		return rule.ipToWire(rule.family(w.RemoteAddr()), serverIp)
+		return rule.ipToWire(rule.family(w.RemoteAddr()), ip)
 
 	case serverPort:
 		_, port, err := net.SplitHostPort(w.LocalAddr().String())