+adt_setup_hook <config> with _config replaced with
+ _setuphook, as for adt_fw_hook
+ Program to run at last moment before we freeze the image.
+ Will be invoked with one argument: the directory containing
+ the root of the testbed. In the future more arguments may be
+ defined, so the hook script should not fail if more are
+ supplied. The supplied hook value will be split at
+ whitespace before execution as if
+ $adt_setup_hook /path/to/root
+ was run from within a shellscript.
+