Better naming (#2104)

* Move functions from pkg/transport to pkg/parse

Although "parse" is a fairly generic name I believe this is somewhat
better named. pkg/transport keeps a few constants that are uses
throughout for the rest is is renaming a bunch (and the fallout from
there to make things compile again).

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

* Fix tests

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

plugin/pkg/parse/transport_test.go

@@ -0,0 +1,25 @@
+package parse
+
+import (
+	"testing"
+
+	"github.com/coredns/coredns/plugin/pkg/transport"
+)
+
+func TestTransport(t *testing.T) {
+	for i, test := range []struct {
+		input    string
+		expected string
+	}{
+		{"dns://.:53", transport.DNS},
+		{"2003::1/64.:53", transport.DNS},
+		{"grpc://example.org:1443 ", transport.GRPC},
+		{"tls://example.org ", transport.TLS},
+		{"https://example.org ", transport.HTTPS},
+	} {
+		actual, _ := Transport(test.input)
+		if actual != test.expected {
+			t.Errorf("Test %d: Expected %s but got %s", i, test.expected, actual)
+		}
+	}
+}