mgcp_test: test_no_cycle: sanitize: free endp

Release endpoint to avoid sanitizer errors.

Change-Id: I78d16ffc435c0f967fe99c6e38dde829b6fa0dc9
diff --git a/tests/mgcp/mgcp_test.c b/tests/mgcp/mgcp_test.c
index 3dee509..da71b46 100644
--- a/tests/mgcp/mgcp_test.c
+++ b/tests/mgcp/mgcp_test.c
@@ -1262,6 +1262,7 @@
 	OSMO_ASSERT(conn->state.stats_cycles == UINT16_MAX + 1);
 	OSMO_ASSERT(conn->state.stats_max_seq == 0);
 
+	mgcp_release_endp(endp);
 	talloc_free(cfg);
 }