fix a c99-ism

src/common/log.c

@@ -1305,7 +1305,8 @@ switch_logs_debug(void)
 void
 truncate_logs(void)
 {
-  for (logfile_t *lf = logfiles; lf; lf = lf->next) {
+  logfile_t *lf;
+  for (lf = logfiles; lf; lf = lf->next) {
     if (lf->fd >= 0) {
       tor_ftruncate(lf->fd);
     }