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

Change-Id: I30151897d621a1428095006e1f0e8a47059de4cd
diff --git a/debian/rules b/debian/rules
index 05bbbef..ef08596 100755
--- a/debian/rules
+++ b/debian/rules
@@ -27,3 +27,6 @@
 	echo $(VERSION) > openbsc/.tarball-version
 	dh_auto_configure --sourcedirectory=openbsc -- --enable-nat --enable-osmo-bsc --enable-smpp
 
+# Print test results in case of a failure
+override_dh_auto_test:
+	dh_auto_test || (find . -name testsuite.log -exec cat {} \; ; false)