MEDIUM: http: The redirect strings follows the log format rules.

We handle "http-request redirect" with a log-format string now, but we
leave "redirect" unaffected.

Note that the control of the special "/" case is move from the runtime
execution to the configuration parsing. If the format rule list is
empty, the build_logline() function does nothing.
diff --git a/include/types/proxy.h b/include/types/proxy.h
index e6bc755..8b9f2fb 100644
--- a/include/types/proxy.h
+++ b/include/types/proxy.h
@@ -403,6 +403,7 @@
 	int type;
 	int rdr_len;
 	char *rdr_str;
+	struct list rdr_fmt;
 	int code;
 	unsigned int flags;
 	int cookie_len;