zebra: Add link parameters support to Zebra

* zebra/interface.c:
   - Add new link-params CLI commands
   - Add new functions to set/get link parameters for interface
* zebra/redistribute.[c,h]: Add new function to propagate link parameters
  to routing daemon (essentially OSPFD and ISISD) for Traffic Engineering.
* zebra/redistribute_null.c: Add new function
  zebra_interface_parameters_update()
* zebra/zserv.[c,h]: Add new functions to send link parameters

Signed-off-by: Olivier Dugeon <olivier.dugeon@orange.com>
diff --git a/zebra/redistribute.h b/zebra/redistribute.h
index 6a36f4d..ce84009 100644
--- a/zebra/redistribute.h
+++ b/zebra/redistribute.h
@@ -48,6 +48,8 @@
 extern void zebra_interface_address_delete_update (struct interface *,
 						   struct connected *c);
 
+extern void zebra_interface_parameters_update (struct interface *);
+
 extern int zebra_check_addr (struct prefix *);
 
 extern int is_default (struct prefix *);