ip: Use specific slave id

The original bond/bridge/vrf and slaves use same id, which make people
confused. Use bond/bridge/vrf_slave as id name will make code more clear.

Acked-by: Phil Sutter <psutter@redhat.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
diff --git a/ip/iplink_vrf.c b/ip/iplink_vrf.c
index 015b41e..a238b29 100644
--- a/ip/iplink_vrf.c
+++ b/ip/iplink_vrf.c
@@ -91,10 +91,9 @@
 };
 
 struct link_util vrf_slave_link_util = {
-	.id             = "vrf",
+	.id             = "vrf_slave",
 	.maxattr        = IFLA_VRF_PORT_MAX,
 	.print_opt	= vrf_slave_print_opt,
-	.slave          = true,
 };
 
 /* returns table id if name is a VRF device */