chunks: change default version discovery to 'iterative'

refs #3771

Change-Id: I67c2589776a122b2e0d790b37e63617eccee9196
diff --git a/tools/chunks/catchunks/ndncatchunks.cpp b/tools/chunks/catchunks/ndncatchunks.cpp
index c877eaa..1f5bd0b 100644
--- a/tools/chunks/catchunks/ndncatchunks.cpp
+++ b/tools/chunks/catchunks/ndncatchunks.cpp
@@ -44,7 +44,7 @@
 {
   std::string programName(argv[0]);
   Options options;
-  std::string discoverType("fixed");
+  std::string discoverType("iterative");
   std::string pipelineType("fixed");
   size_t maxPipelineSize(1);
   int maxRetriesAfterVersionFound(1);