Fix bug in challenge module about component index. Also add some LOG points

Change-Id: I8ec737ef9d7177becbe84055efa2438efab02225
diff --git a/src/ca-module.cpp b/src/ca-module.cpp
index b0d0e44..1e4058c 100644
--- a/src/ca-module.cpp
+++ b/src/ca-module.cpp
@@ -173,6 +173,7 @@
     _LOG_TRACE(e.what());
     return;
   }
+  _LOG_TRACE("SELECT request choosing challenge " << challengeType);
   auto challenge = ChallengeModule::createChallengeModule(challengeType);
   if (challenge == nullptr) {
     _LOG_TRACE("Unrecognized challenge type " << challengeType);