vtysh, zebra: Fix link-params to use exit-link-params

Fix the link-params submode to use the 'exit-link-params'
to indicate we are exiting a submode.

Fixup all the relevant bits.
diff --git a/vtysh/extract.pl.in b/vtysh/extract.pl.in
index 924cffe..ca223e5 100755
--- a/vtysh/extract.pl.in
+++ b/vtysh/extract.pl.in
@@ -54,6 +54,10 @@
 $ignore{'"address-family encapv4"'} = "ignore";
 $ignore{'"address-family encapv6"'} = "ignore";
 $ignore{'"exit-address-family"'} = "ignore";
+$ignore{'"exit-link-params"'} = "ignore";
+$ignore{'"vnc defaults"'} = "ignore";
+$ignore{'"vnc nve-group NAME"'} = "ignore";
+$ignore{'"exit-vnc"'} = "ignore";
 $ignore{'"key chain WORD"'} = "ignore";
 $ignore{'"key <0-2147483647>"'} = "ignore";
 $ignore{'"route-map WORD (deny|permit) <1-65535>"'} = "ignore";