Use a vendor directory for repeatable builds - fixes #816

This is using godep to manage the vendor directory.

vendor/github.com/aws/aws-sdk-go/private/protocol/rest/payload.go

@@ -0,0 +1,45 @@
+package rest
+
+import "reflect"
+
+// PayloadMember returns the payload field member of i if there is one, or nil.
+func PayloadMember(i interface{}) interface{} {
+	if i == nil {
+		return nil
+	}
+
+	v := reflect.ValueOf(i).Elem()
+	if !v.IsValid() {
+		return nil
+	}
+	if field, ok := v.Type().FieldByName("_"); ok {
+		if payloadName := field.Tag.Get("payload"); payloadName != "" {
+			field, _ := v.Type().FieldByName(payloadName)
+			if field.Tag.Get("type") != "structure" {
+				return nil
+			}
+
+			payload := v.FieldByName(payloadName)
+			if payload.IsValid() || (payload.Kind() == reflect.Ptr && !payload.IsNil()) {
+				return payload.Interface()
+			}
+		}
+	}
+	return nil
+}
+
+// PayloadType returns the type of a payload field member of i if there is one, or "".
+func PayloadType(i interface{}) string {
+	v := reflect.Indirect(reflect.ValueOf(i))
+	if !v.IsValid() {
+		return ""
+	}
+	if field, ok := v.Type().FieldByName("_"); ok {
+		if payloadName := field.Tag.Get("payload"); payloadName != "" {
+			if member, ok := v.Type().FieldByName(payloadName); ok {
+				return member.Tag.Get("type")
+			}
+		}
+	}
+	return ""
+}