Added $basename variable to rclocal::script

Now it is possible to have, and select between, more than one rc.local.d
template in one module. This is identical to what monit::fragment does. As
$basename defaults to $modulename, existing modules will not break or require
modifications. This commit contains code (C) Samuli Seppänen taken from the
monit module.

Signed-off-by: Samuli Seppänen <samuli@openvpn.net>
Signed-off-by: Samuli Seppänen <samuli.seppanen@gmail.com>