vty: use VTY_BIND_ADDR_DEFAULT instead of "127.0.0.1"

Change-Id: Ice0688ac9847524cb546f6d41547090b6a3cb3d8
diff --git a/src/vty/vty.c b/src/vty/vty.c
index 8c0c73a..88ed937 100644
--- a/src/vty/vty.c
+++ b/src/vty/vty.c
@@ -1678,7 +1678,7 @@
 		vty_out(vty, " no login%s", VTY_NEWLINE);
 
 	/* bind */
-	if (vty_bind_addr && (strcmp(vty_bind_addr, "127.0.0.1") != 0))
+	if (vty_bind_addr && (strcmp(vty_bind_addr, VTY_BIND_ADDR_DEFAULT) != 0))
 		vty_out(vty, " bind %s%s", vty_bind_addr, VTY_NEWLINE);
 
 	vty_out(vty, "!%s", VTY_NEWLINE);