Update plan to expose unresolvable conflicts

[mikenairn]

What

Update the logic in the plan to include a way to expose the changes we are ignoring due to conflicts that we can't resolve. e.g Record type changing (CNAME -> A).

Why

The plan will currently in a few places detect that it can't do anything and just ignore the change and do nothing. This is the behaviour we want in these situations, but it also doesn't tell you that it did this, so could lead to confusion if you are expecting a record to be a certain way but it isn't.

How

Add a new field to the plan to contain changes that we can't resolve and check that in the dns record controller before applying changes. Conflict errors should be reported back in the status of the DNSRecord.

Requires:

• Gh49 distributed dns plan #79