fw: fix clang compilation error in best-route v2 test case

refs #2179

Change-Id: Ibee6e9c27fd3a0aae7bd1611428f986cff1d1df0
diff --git a/tests/daemon/fw/best-route-strategy2.cpp b/tests/daemon/fw/best-route-strategy2.cpp
index 1c69dfb..3a0005b 100644
--- a/tests/daemon/fw/best-route-strategy2.cpp
+++ b/tests/daemon/fw/best-route-strategy2.cpp
@@ -82,7 +82,8 @@
   scheduler::EventId retxFrom4Evt;
   size_t nSentLast = strategy.m_sendInterestHistory.size();
   time::steady_clock::TimePoint timeSentLast = time::steady_clock::now();
-  function<void()> periodicalRetxFrom4 = [&] {
+  function<void()> periodicalRetxFrom4; // let periodicalRetxFrom4 lambda capture itself
+  periodicalRetxFrom4 = [&] {
     pitEntry->insertOrUpdateInRecord(face4, *interest);
     strategy.afterReceiveInterest(*face4, *interest, fibEntry, pitEntry);