Use --camera properly in debug_viewer

Change-Id: I753a677d9228080977743beb8a10fcd69c1972c0
diff --git a/y2019/vision/debug_viewer.cc b/y2019/vision/debug_viewer.cc
index a919bce..3c174b4 100644
--- a/y2019/vision/debug_viewer.cc
+++ b/y2019/vision/debug_viewer.cc
@@ -332,8 +332,9 @@
 }  // namespace y2017
 
 int main(int argc, char **argv) {
-  y2019::vision::FilterHarness filter_harness;
   ::gflags::ParseCommandLineFlags(&argc, &argv, true);
+
+  y2019::vision::FilterHarness filter_harness;
   aos::vision::DebugFrameworkMain(argc, argv, &filter_harness,
                                   aos::vision::CameraParams());
 }