zebra: fix link-params CLI handling

vtysh was breaking in a rather ugly way, and some "no" forms were
missing too.
diff --git a/zebra/interface.c b/zebra/interface.c
index 5e89db9..c5835f4 100644
--- a/zebra/interface.c
+++ b/zebra/interface.c
@@ -2636,6 +2636,7 @@
   if (IS_PARAM_SET(iflp, LP_RMT_AS))
     vty_out(vty, "  neighbor %s as %u%s", inet_ntoa(iflp->rmt_ip),
         iflp->rmt_as, VTY_NEWLINE);
+  vty_out(vty, "  exit%s", VTY_NEWLINE);
   return 0;
 }
 
@@ -2786,13 +2787,20 @@
   install_element(LINK_PARAMS_NODE, &link_params_max_rsv_bw_cmd);
   install_element(LINK_PARAMS_NODE, &link_params_unrsv_bw_cmd);
   install_element(LINK_PARAMS_NODE, &link_params_admin_grp_cmd);
+  install_element(LINK_PARAMS_NODE, &no_link_params_admin_grp_cmd);
   install_element(LINK_PARAMS_NODE, &link_params_inter_as_cmd);
   install_element(LINK_PARAMS_NODE, &no_link_params_inter_as_cmd);
   install_element(LINK_PARAMS_NODE, &link_params_delay_cmd);
+  install_element(LINK_PARAMS_NODE, &no_link_params_delay_cmd);
   install_element(LINK_PARAMS_NODE, &link_params_delay_mm_cmd);
   install_element(LINK_PARAMS_NODE, &link_params_delay_var_cmd);
+  install_element(LINK_PARAMS_NODE, &no_link_params_delay_var_cmd);
   install_element(LINK_PARAMS_NODE, &link_params_pkt_loss_cmd);
+  install_element(LINK_PARAMS_NODE, &no_link_params_pkt_loss_cmd);
   install_element(LINK_PARAMS_NODE, &link_params_ava_bw_cmd);
+  install_element(LINK_PARAMS_NODE, &no_link_params_ava_bw_cmd);
   install_element(LINK_PARAMS_NODE, &link_params_res_bw_cmd);
+  install_element(LINK_PARAMS_NODE, &no_link_params_res_bw_cmd);
   install_element(LINK_PARAMS_NODE, &link_params_use_bw_cmd);
+  install_element(LINK_PARAMS_NODE, &no_link_params_use_bw_cmd);
 }