add rudimentary NRI support for MSC pooling

This patch served for a manual testing counterpart for osmo-bsc to implement
MSC pooling.

This enables a basic MSC pooling setup, but for a production setup, osmo-msc
would still lack various features related to unloading subscribers to another
MSC as explained in 3GPP TS 23.236.

Change-Id: Iafe0878a0a2c8669080d757b34a398ea75fced36
diff --git a/tests/test_nodes.vty b/tests/test_nodes.vty
index edb891b..520f07c 100644
--- a/tests/test_nodes.vty
+++ b/tests/test_nodes.vty
@@ -63,6 +63,9 @@
   no sms-over-gsup
   osmux (on|off|only)
   handover-number range MSISDN_FIRST MSISDN_LAST
+  nri bitlen <0-15>
+  nri add <0-32767> [<0-32767>]
+  nri del <0-32767> [<0-32767>]
   neighbor (a|iu) lac <0-65535> (ran-pc|msc-ipa-name) RAN_PC_OR_MSC_IPA_NAME
   neighbor (a|iu) lac-ci <0-65535> <0-65535> (ran-pc|msc-ipa-name) RAN_PC_OR_MSC_IPA_NAME
   neighbor (a|iu) cgi <0-999> <0-999> <0-65535> <0-65535> (ran-pc|msc-ipa-name) RAN_PC_OR_MSC_IPA_NAME