Comment 1 for bug 2028692

That timeout is hardcoded in autopkgtest-virt-ssh:

        (status, out, err) = VirtSubproc.execute_timeout(
            None,
            1800,
            cmd,
            stdout=subprocess.PIPE,
            stderr=subprocess.PIPE)

We could add a --timeout-setup-script flag to override it (to be submitted upstream). Should be easy to do.