Core/Misc: Fix issues reported by static analysis

Coverity defect IDs: 1316687, 1316688

src/common/Logging/Log.cpp

@@ -27,7 +27,7 @@
 #include <cstdio>
 #include <sstream>
 
-Log::Log() : _ioService(nullptr), _strand(nullptr)
+Log::Log() : AppenderId(0), lowestLogLevel(LOG_LEVEL_FATAL), _ioService(nullptr), _strand(nullptr)
 {
     m_logsTimestamp = "_" + GetTimestampStr();
     RegisterAppender<AppenderConsole>();