debian/rules: show testsuite.log when tests are failing

Change-Id: Ice1c9f51225cef335626d5689ffb306395d7e2b6
diff --git a/debian/rules b/debian/rules
index 03432e6..3e2c91f 100755
--- a/debian/rules
+++ b/debian/rules
@@ -16,3 +16,7 @@
 override_dh_strip:
 	dh_strip --dbg-package=libosmo-ranap-dbg
 	dh_strip --dbg-package=osmo-hnbgw
+
+# Print test results in case of a failure
+override_dh_auto_test:
+	dh_auto_test || (find . -name testsuite.log -exec cat {} \; ; false)