Make #maxRedirects and #followRedirects work for the dart:io HTTP client.

pkg/http/lib/src/io_client.dart

Index: pkg/http/lib/src/io_client.dart
diff --git a/pkg/http/lib/src/io_client.dart b/pkg/http/lib/src/io_client.dart
index 995ff3b1d9e60cf163af424b3ba769110056932c..48416cea5b809ae3de94d6946be5d0cc65536e85 100644
--- a/pkg/http/lib/src/io_client.dart
+++ b/pkg/http/lib/src/io_client.dart
@@ -25,6 +25,8 @@ class IOClient extends BaseClient {
 
     var completer = new Completer<StreamedResponse>();
     var connection = _inner.openUrl(request.method, request.url);
+    connection.followRedirects = request.followRedirects;
+    connection.maxRedirects = request.maxRedirects;
     connection.onError = (e) {
       async.then((_) {
         // TODO(nweiz): remove this when issue 4974 is fixed