reset descriptor to -1 after closing file in rotate

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@7976 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/mod/event_handlers/mod_cdr_csv/mod_cdr_csv.c

@@ -85,6 +85,7 @@ static void do_rotate(cdr_fd_t *fd)
 	size_t len;
 
 	close(fd->fd);
+	fd->fd = -1;
 
 	if (globals.rotate) {
 		switch_time_exp_lt(&tm, switch_timestamp_now());