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_hlr_reject.err b/tests/msc_vlr/msc_vlr_test_hlr_reject.err
index f0d94b4..51fc0e8 100644
--- a/tests/msc_vlr/msc_vlr_test_hlr_reject.err
+++ b/tests/msc_vlr/msc_vlr_test_hlr_reject.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_hlr_rej_auth_info_unknown_imsi
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -101,7 +101,7 @@
 ===== test_hlr_rej_auth_info_unknown_imsi: 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_hlr_rej_auth_info_net_fail
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -202,7 +202,7 @@
 ===== test_hlr_rej_auth_info_net_fail: 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_hlr_rej_auth_info_net_fail_reuse_tuples
 
@@ -528,7 +528,7 @@
 ===== test_hlr_rej_auth_info_net_fail_reuse_tuples: 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_hlr_rej_auth_info_net_fail_no_reuse_tuples
 
@@ -794,7 +794,7 @@
 ===== test_hlr_rej_auth_info_net_fail_no_reuse_tuples: 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_hlr_rej_auth_info_unkown_imsi_no_reuse_tuples
 
@@ -1061,7 +1061,7 @@
 ===== test_hlr_rej_auth_info_unkown_imsi_no_reuse_tuples: 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_hlr_acc_but_no_auth_tuples
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -1161,7 +1161,7 @@
 ===== test_hlr_acc_but_no_auth_tuples: 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_hlr_rej_lu
 - Location Update request causes a GSUP LU request to HLR
@@ -1264,7 +1264,7 @@
 ===== test_hlr_rej_lu: 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_hlr_no_insert_data
 - Location Update request causes a GSUP LU request to HLR
@@ -1380,8 +1380,8 @@
 ===== test_hlr_no_insert_data: 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