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.hpp b/daemon/fw/forwarder.hpp
index c3898c6..51a75dc 100644
--- a/daemon/fw/forwarder.hpp
+++ b/daemon/fw/forwarder.hpp
@@ -32,6 +32,9 @@
 public:
   Forwarder();
 
+  VIRTUAL_WITH_TESTS
+  ~Forwarder();
+
   const ForwarderCounters&
   getCounters() const;