core: change logging from environment variable to configuration file-based

GlobalConfigurationFixture uses unit-tests.conf to determine default
and module specific logging levels. Logging will gracefully default to
INFO if unit-tests.conf is not found. See unit-tests.conf.sample for a
sample configuration file.

refs: #1375, #1267

Change-Id: Ib0c4eb4149748e6658f94ef1afa23ddd3072c0fa
diff --git a/daemon/fw/forwarder.cpp b/daemon/fw/forwarder.cpp
index 58ce5a3..8ffda2f 100644
--- a/daemon/fw/forwarder.cpp
+++ b/daemon/fw/forwarder.cpp
@@ -6,6 +6,7 @@
 
 #include "forwarder.hpp"
 #include "available-strategies.hpp"
+#include "core/logger.hpp"
 
 namespace nfd {
 
@@ -26,6 +27,11 @@
   fw::installStrategies(*this);
 }
 
+Forwarder::~Forwarder()
+{
+
+}
+
 void
 Forwarder::onIncomingInterest(Face& inFace, const Interest& interest)
 {