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

Change-Id: If0b10c02f87ed81878593198e21da1fc9f8d4bbc
diff --git a/debian/rules b/debian/rules
index d0ad702..1d8d8ab 100755
--- a/debian/rules
+++ b/debian/rules
@@ -11,3 +11,7 @@
 
 override_dh_strip:
 	dh_strip --dbg-package=osmo-hlr-dbg
+
+# Print test results in case of a failure
+override_dh_auto_test:
+	dh_auto_test || (find . -name testsuite.log -exec cat {} \; ; false)