Fix build.

R=sgjesse@google.com
BUG=

Review URL: https://chromiumcodereview.appspot.com//1209533002
diff --git a/lib/protobuf.dart b/lib/protobuf.dart
index 50926d4..f0ed4e0 100644
--- a/lib/protobuf.dart
+++ b/lib/protobuf.dart
@@ -24,7 +24,7 @@
 part 'src/protobuf/generated_service.dart';
 part 'src/protobuf/pb_list.dart';
 part 'src/protobuf/protobuf_enum.dart';
-part 'src/protobuf/rpc_client';
+part 'src/protobuf/rpc_client.dart';
 part 'src/protobuf/unknown_field_set.dart';
 part 'src/protobuf/utils.dart';
 part 'src/protobuf/wire_format.dart';