In Start_log_event::print, don't print "created 1970 etc" if created == 0.

Otherwise, we'll get questions from users about this curious 1970.

sql/log_event.cc

@@ -302,9 +302,13 @@ void Start_log_event::print(FILE* file, bool short_form, char* last_db)
     return;
 
   print_header(file);
-  fprintf(file, "\tStart: binlog v %d, server v %s created ", binlog_version,
+  fprintf(file, "\tStart: binlog v %d, server v %s", binlog_version,
 	  server_version);
+  if (created)
+  {
+    fprintf(file, " created ");
     print_timestamp(file, &created);
+  }
   fputc('\n', file);
   fflush(file);
 }