Remove debug code.

Author: szmyd

gcovr.cfg

@@ -7,6 +7,9 @@ exclude = .*build.*
 exclude = .*flip.*
 exclude = .*generate.*
 exclude = .*test.*
+exclude = .*backtrace.cpp
+exclude = .*stacktrace.cpp
+exclude = .*callback_mutex.hpp
 
 exclude-lines-by-pattern = .*DEBUG.*
 exclude-lines-by-pattern = .*DBG.*