gtphub: add test for reused TEI.

Sponsored-by: On-Waves ehi
diff --git a/openbsc/tests/gtphub/gtphub_test.ok b/openbsc/tests/gtphub/gtphub_test.ok
index dbc8a6e..b37b7d7 100644
--- a/openbsc/tests/gtphub/gtphub_test.ok
+++ b/openbsc/tests/gtphub/gtphub_test.ok
@@ -9,4 +9,9 @@
 - __wrap_gtphub_resolve_ggsn_addr():
   returning GGSN addr from imsi 240010123456789 ni internet: 192.168.43.34 port 2123
 - user data starts
+test_reused_tei
+- __wrap_gtphub_resolve_ggsn_addr():
+  returning GGSN addr from imsi 240010123456789 ni internet: 192.168.43.34 port 2123
+- __wrap_gtphub_resolve_ggsn_addr():
+  returning GGSN addr from imsi 240010123456789 ni internet: 192.168.43.34 port 2123
 Done