catchunks: simplify internal options handling

Change-Id: I537a281f6c996c2544c145ab9cc01a54272c8efa
diff --git a/tools/chunks/catchunks/pipeline-interests-aimd.hpp b/tools/chunks/catchunks/pipeline-interests-aimd.hpp
index b83dfd6..f76163e 100644
--- a/tools/chunks/catchunks/pipeline-interests-aimd.hpp
+++ b/tools/chunks/catchunks/pipeline-interests-aimd.hpp
@@ -40,8 +40,7 @@
 class PipelineInterestsAimd final : public PipelineInterestsAdaptive
 {
 public:
-  PipelineInterestsAimd(Face& face, RttEstimatorWithStats& rttEstimator,
-                        const Options& options = Options());
+  PipelineInterestsAimd(Face& face, RttEstimatorWithStats& rttEstimator, const Options& opts);
 
 private:
   void