Reduce scope of temp camera file

api.cpp

@@ -131,6 +131,9 @@ class Context {
 
   val captureImageAsFile() {
     return gpp_rethrow([=]() {
+      auto &file = get_file();
+
+      {
         struct TempCameraFile {
           Camera &camera;
           GPContext &context;
@@ -152,10 +155,10 @@ class Context {
         gpp_try(gp_camera_capture(camera.get(), GP_CAPTURE_IMAGE,
                                   &camera_file.path, context.get()));
 
-      auto &file = get_file();
         gpp_try(gp_camera_file_get(camera.get(), camera_file.path.folder,
                                    camera_file.path.name, GP_FILE_TYPE_NORMAL,
                                    &file, context.get()));
+      }
 
       gpp_try(gp_file_set_name(&file, "image."));
       gpp_try(gp_file_adjust_name_for_mime_type(&file));