Fix mysql monothread test. (#5667)

frameworks/C++/lithium/lithium.cc

@@ -75,18 +75,12 @@ int main(int argc, char* argv[]) {
 
   int nprocs = std::thread::hardware_concurrency();
 
-#if TFB_MYSQL
-  int nthreads = nprocs;
-#elif TFB_PGSQL
-
 #if MONOTHREAD
   int nthreads = 1;
 #else
   int nthreads = nprocs;
 #endif
 
-#endif
-
 #if TFB_MYSQL
   auto sql_db = mysql_database(s::host = argv[1], s::database = "hello_world", s::user = "benchmarkdbuser",
                 s::password = "benchmarkdbpass", s::port = 3306, s::charset = "utf8");