_ALWAYS_CLEAN_LOGS when defined cleans log away when ending application

[abumq]

if you have _END_EASYLOGGINGPP in the middle of application and have _ALWAYS_CLEAN_LOGS defined, it cleans out all the logs every time we re-log something after _END_EASYLOGGINGPP

For example:

 int sum(int a, int b) {
   INFO("Adding " << a << " and " << b);
   _END_EASYLOGGINGPP
   return a+b;
 }
 int main() {
   sum(1,2);
   INFO("..."); // this will clean the logs (if compiled using `-D _ALWAYS_CLEAN_LOGS`) since we have `END_EASYLOGGINGPP` in sum(..)
   _END_EASYLOGGINGPP
 }

FUNC(int, main, (int argc, char** argv))

   _END_EASYLOGGING
END_FUNC(0)

because END_FUNC macro logs performance of function so the logs are cleaned out (because of preceeding _END_EASYLOGGINGPP)