Fix subresource sync issues

Fix subresource identity function

The identity function is supposed to uniquely identify a subresource in a set for the purpose of detecting defaults. At its most basic, it’s supposed to just just remove the ensure attribute and compute the hash so you can’t have two otherwise identical subresources with different values for ensure.

Previously it stripped an attribute called absent rather than the ensure attribute.

Fix set comparison

Previously, entries in sets were considered to be unchanged if their identities were the same. In particular, it ignored most changes to ensure. This adds code to make sure that entries with the same identity are actually unchanged.

This also adds a warning when there’s an error normalizing and deduplicating the is array.

To do

[x] Maybe remove warning? not really a bad thing I guess?
[x] Add tests

danielparks / puppet-rustup