logging: print talloc report on exit from vty test

There's not much point in deallocating memory in a test fixture
which is about to terminate anyway. Having talloc report though
is handy to make sure we're not leaking smth.

Change-Id: I5739bceb90d36164fd4cbf21242bbe26bd1e7075
diff --git a/tests/logging/logging_vty_test.c b/tests/logging/logging_vty_test.c
index 15f7fc2..c1a2853 100644
--- a/tests/logging/logging_vty_test.c
+++ b/tests/logging/logging_vty_test.c
@@ -285,10 +285,10 @@
 		osmo_select_main(0);
 	}
 
-	log_fini();
+	talloc_report(tall_vty_ctx, stderr);
+	talloc_report_full(root_ctx, stderr);
 
-	talloc_free(root_ctx);
-	talloc_free(tall_vty_ctx);
+	log_fini();
 
 	return 0;
 }