gb: Fix gprs_nsvc_delete() to free ctr group

This fixes a SEGV error that happens the next time the statistics
are updated.

Addresses:
 Program terminated with signal 11, Segmentation fault.
 #0  0xb7711fa5 in rate_ctr_group_intv (grp=<optimized out>) at
 rate_ctr.c:107
 107             for (i = 0; i < grp->desc->num_ctr; i++) {
 #0  0xb7711fa5 in rate_ctr_group_intv (grp=<optimized out>) at
     rate_ctr.c:107
 #1  rate_ctr_timer_cb (data=0x0) at rate_ctr.c:129
 #2  0xb770ec59 in osmo_timers_update () at timer.c:243
 #3  0xb770ef7a in osmo_select_main (polling=0) at select.c:133
 #4  0x08049987 in main (argc=3, argv=0xbfba8084) at
     gb_proxy_main.c:306

Sponsored-by: On-Waves ehf
diff --git a/tests/gb/gprs_ns_test.ok b/tests/gb/gprs_ns_test.ok
index 424d681..b5d578a 100644
--- a/tests/gb/gprs_ns_test.ok
+++ b/tests/gb/gprs_ns_test.ok
@@ -1,4 +1,90 @@
 ===== NS protocol test START
+--- Create via RESET (round 0) ---
+
+PROCESSING RESET from 0x01020304:1111
+02 00 81 01 01 82 10 01 04 82 10 00 
+
+==> got signal NS_RESET, NS-VC 0x1001/1.2.3.4:1111
+MESSAGE to BSS, msg length 9
+03 01 82 10 01 04 82 10 00 
+
+MESSAGE to BSS, msg length 1
+0a 
+
+result (RESET) = 9
+
+Current NS-VCIs:
+    VCI 0x1001, NSEI 0x1000, peer 0x01020304:1111, blocked
+
+--- Delete nsvc object (round 0)---
+
+Current NS-VCIs:
+
+--- Create via RESET (round 1) ---
+
+PROCESSING RESET from 0x01020304:1111
+02 00 81 01 01 82 10 01 04 82 10 00 
+
+==> got signal NS_RESET, NS-VC 0x1001/1.2.3.4:1111
+MESSAGE to BSS, msg length 9
+03 01 82 10 01 04 82 10 00 
+
+MESSAGE to BSS, msg length 1
+0a 
+
+result (RESET) = 9
+
+Current NS-VCIs:
+    VCI 0x1001, NSEI 0x1000, peer 0x01020304:1111, blocked
+
+--- Delete nsvc object (round 1)---
+
+Current NS-VCIs:
+
+--- Create via RESET (round 2) ---
+
+PROCESSING RESET from 0x01020304:1111
+02 00 81 01 01 82 10 01 04 82 10 00 
+
+==> got signal NS_RESET, NS-VC 0x1001/1.2.3.4:1111
+MESSAGE to BSS, msg length 9
+03 01 82 10 01 04 82 10 00 
+
+MESSAGE to BSS, msg length 1
+0a 
+
+result (RESET) = 9
+
+Current NS-VCIs:
+    VCI 0x1001, NSEI 0x1000, peer 0x01020304:1111, blocked
+
+--- Delete nsvc object (round 2)---
+
+Current NS-VCIs:
+
+--- Create via RESET (round 3) ---
+
+PROCESSING RESET from 0x01020304:1111
+02 00 81 01 01 82 10 01 04 82 10 00 
+
+==> got signal NS_RESET, NS-VC 0x1001/1.2.3.4:1111
+MESSAGE to BSS, msg length 9
+03 01 82 10 01 04 82 10 00 
+
+MESSAGE to BSS, msg length 1
+0a 
+
+result (RESET) = 9
+
+Current NS-VCIs:
+    VCI 0x1001, NSEI 0x1000, peer 0x01020304:1111, blocked
+
+--- Delete nsvc object (round 3)---
+
+Current NS-VCIs:
+
+--- Process timers ---
+
 --- Setup, send BSSGP RESET ---
 
 Setup NS-VC: remote 0x01020304:1111, NSVCI 0x1122(4386), NSEI 0x1122(4386)