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_no_authen.err b/tests/msc_vlr/msc_vlr_test_no_authen.err
index 2ee21da..a74c18f 100644
--- a/tests/msc_vlr/msc_vlr_test_no_authen.err
+++ b/tests/msc_vlr/msc_vlr_test_no_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_no_authen
 - Location Update request causes a GSUP LU request to HLR
@@ -451,7 +451,7 @@
 ===== test_no_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_no_authen_tmsi
 - Location Update request causes a GSUP LU request to HLR
@@ -1134,7 +1134,7 @@
 ===== test_no_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_no_authen_imei
 - Location Update request causes a GSUP LU request to HLR
@@ -1385,7 +1385,7 @@
 ===== test_no_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_no_authen_tmsi_imei
 - Location Update request causes a GSUP LU request to HLR
@@ -1671,7 +1671,7 @@
 ===== test_no_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_no_authen_imeisv
 - Location Update request causes an IMEISV ID request back to the MS
@@ -1892,7 +1892,7 @@
 ===== test_no_authen_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_no_authen_imeisv_imei
 - Location Update request causes an IMEISV ID request back to the MS
@@ -2124,7 +2124,7 @@
 ===== test_no_authen_imeisv_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_no_authen_imeisv_tmsi
 - Location Update request causes an IMEISV ID request back to the MS
@@ -2590,7 +2590,7 @@
 ===== test_no_authen_imeisv_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_no_authen_imeisv_tmsi_imei
 - Location Update request causes an IMEISV ID request back to the MS
@@ -2859,7 +2859,7 @@
 ===== test_no_authen_imeisv_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_no_authen_subscr_expire
 - Total time passed: 0.000000 s
@@ -2994,8 +2994,8 @@
 ===== test_no_authen_subscr_expire: 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