Fix a bug with mojom imports where 2 imports with the same namespace would

mojo/public/bindings/tests/sample_service.mojom

Index: mojo/public/bindings/tests/sample_service.mojom
diff --git a/mojo/public/bindings/tests/sample_service.mojom b/mojo/public/bindings/tests/sample_service.mojom
index 3bd4c43b8e136b5b81b2d9a08405aeebc1e46692..0a15257c9ceb59f11f3f96410ea02a40b0e1674d 100644
--- a/mojo/public/bindings/tests/sample_service.mojom
+++ b/mojo/public/bindings/tests/sample_service.mojom
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 import "sample_import.mojom"
+import "sample_import2.mojom"
 
 module sample {
 
@@ -47,6 +48,7 @@ struct DefaultsTest {
   uint8[] data = [1, 2, 3] @2;
   imported.Point point = {7, 15} @3;
   int32[] shape_masks = [1 << imported.SHAPE_RECTANGLE] @4;
+  imported.Thing thing = {imported.SHAPE_RECTANGLE, imported.COLOR_RED};
 };
 
 interface Port {