go report card fixes (#3182)

Went over the list at https://goreportcard.com/report/github.com/coredns/coredns
and removed/fix some code to make it slightly happier.

Signed-off-by: Miek Gieben <miek@miek.nl>

plugin/etcd/msg/service_test.go

@@ -123,12 +123,3 @@ func TestGroup(t *testing.T) {
 		t.Fatalf("Failure to group seventh set: %v", sx)
 	}
 }
-
-func BenchmarkNewSRV(b *testing.B) {
-	s := &Service{Host: "www,example.org", Port: 8080}
-	for n := 0; n < b.N; n++ {
-		srv := s.NewSRV("www.example.org.", 16)
-		// this assignment makes sure s.NewSRV doesn't get optimized out
-		srv = srv
-	}
-}