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/msc_vlr/msc_vlr_test_gsm_ciph.err b/tests/msc_vlr/msc_vlr_test_gsm_ciph.err
index e753096..edd4ee6 100644
--- a/tests/msc_vlr/msc_vlr_test_gsm_ciph.err
+++ b/tests/msc_vlr/msc_vlr_test_gsm_ciph.err
@@ -1,6 +1,6 @@
 DLMGCP MGCP client: using endpoint domain '@mgw'
 full talloc report on 'msgb' (total      0 bytes in   1 blocks)
-talloc_total_blocks(tall_bsc_ctx) == 19
+talloc_total_blocks(tall_bsc_ctx) == 20
 
 ===== test_ciph
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -652,7 +652,7 @@
 ===== test_ciph: SUCCESS
 
 full talloc report on 'msgb' (total      0 bytes in   1 blocks)
-talloc_total_blocks(tall_bsc_ctx) == 19
+talloc_total_blocks(tall_bsc_ctx) == 20
 
 ===== test_ciph_tmsi
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -1352,7 +1352,7 @@
 ===== test_ciph_tmsi: SUCCESS
 
 full talloc report on 'msgb' (total      0 bytes in   1 blocks)
-talloc_total_blocks(tall_bsc_ctx) == 19
+talloc_total_blocks(tall_bsc_ctx) == 20
 
 ===== test_ciph_imei
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -1671,7 +1671,7 @@
 ===== test_ciph_imei: SUCCESS
 
 full talloc report on 'msgb' (total      0 bytes in   1 blocks)
-talloc_total_blocks(tall_bsc_ctx) == 19
+talloc_total_blocks(tall_bsc_ctx) == 20
 
 ===== test_ciph_imeisv
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -1955,7 +1955,7 @@
 ===== test_ciph_imeisv: SUCCESS
 
 full talloc report on 'msgb' (total      0 bytes in   1 blocks)
-talloc_total_blocks(tall_bsc_ctx) == 19
+talloc_total_blocks(tall_bsc_ctx) == 20
 
 ===== test_ciph_tmsi_imei
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -2315,7 +2315,7 @@
 ===== test_ciph_tmsi_imei: SUCCESS
 
 full talloc report on 'msgb' (total      0 bytes in   1 blocks)
-talloc_total_blocks(tall_bsc_ctx) == 19
+talloc_total_blocks(tall_bsc_ctx) == 20
 
 ===== test_gsm_ciph_in_umts_env
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -2912,7 +2912,7 @@
 ===== test_gsm_ciph_in_umts_env: SUCCESS
 
 full talloc report on 'msgb' (total      0 bytes in   1 blocks)
-talloc_total_blocks(tall_bsc_ctx) == 19
+talloc_total_blocks(tall_bsc_ctx) == 20
 
 ===== test_a5_3_supported
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -3556,7 +3556,7 @@
 ===== test_a5_3_supported: SUCCESS
 
 full talloc report on 'msgb' (total      0 bytes in   1 blocks)
-talloc_total_blocks(tall_bsc_ctx) == 19
+talloc_total_blocks(tall_bsc_ctx) == 20
 
 ===== test_cm_service_needs_classmark_update
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -4178,8 +4178,8 @@
 ===== test_cm_service_needs_classmark_update: SUCCESS
 
 full talloc report on 'msgb' (total      0 bytes in   1 blocks)
-talloc_total_blocks(tall_bsc_ctx) == 19
+talloc_total_blocks(tall_bsc_ctx) == 20
 
 full talloc report on 'msgb' (total      0 bytes in   1 blocks)
-talloc_total_blocks(tall_bsc_ctx) == 19
+talloc_total_blocks(tall_bsc_ctx) == 20