services_autorun fails due to evaluation order

@services_autorun@ doesn't work as documented in 3.6.x: from the command line it's fine to say @-Dservices_autorun@ but if you enable it in @def.cf@, you get an error:

<pre>
2014-05-29T20:31:51+0000 error: Bundle 'autorun' listed in the bundlesequence is not a defined bundle
2014-05-29T20:31:51+0000 error: Fatal CFEngine error: Errors in promise bundles: could not verify bundlesequence
</pre>

This happens because the class is evaluated too late in policy.

This is a fairly severe problem and the remedy is low-risk policy-only.

The fix is in @master@ thanks to Nick, but needs CCB review for possibly going into 3.6.0. Please see https://github.com/cfengine/masterfiles/pull/257 for the prepared patch (it doesn't cherry-pick cleanly from @master@). If it doesn't pass CCB then it can target 3.6.1 but I have to document the workaround and the problem in a special 3.6.x commit for 3.6.0.