debian: override_dh_clean to include gnutls files

Change-Id: I0c2b1d38dc8c1b4c8a81b2aa392121c6539fca44
Reviewed-by: Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>

packaging/rules/debian/rules

@@ -122,6 +122,12 @@ override_dh_auto_clean:
 	if [ -f client-gnome/build/Makefile ]; then make -C client-gnome/build distclean; fi
 	rm -rfv client-gnome/build
 
+override_dh_clean:
+	# GNUTLS contains:
+	# ring-project/daemon/contrib/tarballs-unpacked/gnutls-3.5.10.tar.xz/gnutls-3.5.10/src/certtool-args.c.bak
+	# ring-project/daemon/contrib/tarballs-unpacked/gnutls-3.5.10.tar.xz/gnutls-3.5.10/doc/doxygen/Doxyfile.orig
+	dh_clean -X.bak -X.orig
+
 override_dh_auto_install:
 	#########################
 	## Ring Daemon install ##