Also change example script

Author: Daniel Dunn

src/variants/example/post_chroot_script

@@ -8,4 +8,8 @@ install_chroot_fail_on_error_trap
 unpack /filesystem/root /
 
 #cleanup
-apt-get clean
+if [ -n "$BASE_APT_CACHE" ] && [ "$BASE_APT_CACHE" != "no" ]; then
+  apt-get autoclean
+else
+  apt-get clean
+fi