fix object storage nil pointer deref error
diff --git a/rackspace/objectstorage/v1/bulk/requests.go b/rackspace/objectstorage/v1/bulk/requests.go
index 898b73b..0aeec15 100644
--- a/rackspace/objectstorage/v1/bulk/requests.go
+++ b/rackspace/objectstorage/v1/bulk/requests.go
@@ -43,7 +43,9 @@
 		JSONBody:     reqBody,
 		JSONResponse: &res.Body,
 	})
-	res.Header = resp.Header
+	if resp != nil {
+		res.Header = resp.Header
+	}
 	res.Err = err
 	return res
 }