support/scripts/test-pkg: extend logfile with olddefconfig output

Signed-off-by: Benoît Allard <benoit.allard@greenbone.net>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

support/scripts/test-pkg

@@ -108,7 +108,7 @@ build_one() {
 	_EOF_
     cat "${cfg}" >>"${dir}/.config"
 
-    if ! make O="${dir}" olddefconfig >/dev/null 2>&1; then
+    if ! make O="${dir}" olddefconfig > "${dir}/logfile" 2>&1; then
         printf "FAILED\n"
         return 2
     fi