private/model/api: Fix RESTXML support for XML Namespace (#1343)

Fixes a bug with the SDK's generation of services using the REST XML
protocol not annotating shape references with the XML Namespace
attribute.

The XML Namespace URI was incorrectly being limited to the top level
API shape, where it should of applied to all levels.

Fix #1334

private/model/api/shape.go

@@ -400,16 +400,18 @@ func (ref *ShapeRef) GoTags(toplevel bool, isRequired bool) string {
 		if ref.Shape.Payload != "" {
 			tags = append(tags, ShapeTag{"payload", ref.Shape.Payload})
 		}
-		if ref.XMLNamespace.Prefix != "" {
-			tags = append(tags, ShapeTag{"xmlPrefix", ref.XMLNamespace.Prefix})
-		} else if ref.Shape.XMLNamespace.Prefix != "" {
-			tags = append(tags, ShapeTag{"xmlPrefix", ref.Shape.XMLNamespace.Prefix})
-		}
-		if ref.XMLNamespace.URI != "" {
-			tags = append(tags, ShapeTag{"xmlURI", ref.XMLNamespace.URI})
-		} else if ref.Shape.XMLNamespace.URI != "" {
-			tags = append(tags, ShapeTag{"xmlURI", ref.Shape.XMLNamespace.URI})
-		}
+	}
+
+	if ref.XMLNamespace.Prefix != "" {
+		tags = append(tags, ShapeTag{"xmlPrefix", ref.XMLNamespace.Prefix})
+	} else if ref.Shape.XMLNamespace.Prefix != "" {
+		tags = append(tags, ShapeTag{"xmlPrefix", ref.Shape.XMLNamespace.Prefix})
+	}
+
+	if ref.XMLNamespace.URI != "" {
+		tags = append(tags, ShapeTag{"xmlURI", ref.XMLNamespace.URI})
+	} else if ref.Shape.XMLNamespace.URI != "" {
+		tags = append(tags, ShapeTag{"xmlURI", ref.Shape.XMLNamespace.URI})
 	}
 
 	if ref.IdempotencyToken || ref.Shape.IdempotencyToken {

private/protocol/restxml/build_test.go

@@ -3586,7 +3586,7 @@ func (c *InputService19ProtocolTest) InputService19TestCaseOperation1WithContext
 type InputService19TestShapeGrant struct {
 	_ struct{} `locationName:"Grant" type:"structure"`
 
-	Grantee *InputService19TestShapeGrantee `type:"structure"`
+	Grantee *InputService19TestShapeGrantee `type:"structure" xmlPrefix:"xsi" xmlURI:"http://www.w3.org/2001/XMLSchema-instance"`
 }
 
 // SetGrantee sets the Grantee field's value.