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_authen.err b/tests/msc_vlr/msc_vlr_test_gsm_authen.err
index 7042355..3da091f 100644
--- a/tests/msc_vlr/msc_vlr_test_gsm_authen.err
+++ b/tests/msc_vlr/msc_vlr_test_gsm_authen.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_gsm_authen
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -584,7 +584,7 @@
 ===== test_gsm_authen: 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_authen_tmsi
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -1407,7 +1407,7 @@
 ===== test_gsm_authen_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_gsm_authen_imei
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -1719,7 +1719,7 @@
 ===== test_gsm_authen_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_authen_imei_nack
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -1984,7 +1984,7 @@
 ===== test_gsm_authen_imei_nack: 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_authen_imei_err
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -2250,7 +2250,7 @@
 ===== test_gsm_authen_imei_err: 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_authen_tmsi_imei
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -2603,7 +2603,7 @@
 ===== test_gsm_authen_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_milenage_authen
 - Location Update request causes a GSUP Send Auth Info request to HLR
@@ -3161,7 +3161,7 @@
 ===== test_gsm_milenage_authen: 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_wrong_sres_length
 - Total time passed: 0.000000 s
@@ -3306,8 +3306,8 @@
 ===== test_wrong_sres_length: 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