Retire struct Log

No more used now that we have removed
"Write Search Log" UCI option.

No functional change.

src/misc.cpp

@@ -17,6 +17,7 @@
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
 
+#include <fstream>
 #include <iomanip>
 #include <iostream>
 #include <sstream>

src/misc.h

@@ -20,7 +20,7 @@
 #ifndef MISC_H_INCLUDED
 #define MISC_H_INCLUDED
 
-#include <fstream>
+#include <ostream>
 #include <string>
 #include <vector>
 
@@ -37,12 +37,6 @@ extern void dbg_mean_of(int v);
 extern void dbg_print();
 
 
-struct Log : public std::ofstream {
-  Log(const std::string& f = "log.txt") : std::ofstream(f.c_str(), std::ios::out | std::ios::app) {}
- ~Log() { if (is_open()) close(); }
-};
-
-
 namespace Time {
   typedef int64_t point;
   inline point now() { return system_time_to_msec(); }