Apply Single Zone Settings on Delete

[tootedom]

The singleZoneSettings, for example h2_prioritization, are not reverted in the Delete function.
The result being if you run terratest (or terraform acceptance tests) you end up with the error:

Error: errors during apply: error from makeRequest: HTTP status 400: content "{\"success\":false,\"errors\":[{\"code\":1006,\"message\":\"Unrecognized zone setting name\"}],\"messages\":[],\"result\":null}"

As h2_prioritization, and the other singleZoneSettings are trying to be applied in the UpdateZoneSettings client request, in the delete function. The cloudflare api isn't allowing the single zone settings of h2_prioritization to be set in UpdateZoneSettings, but requires the to be applied in ZoneSingleSetting.

This has been catered for in all other methods, but the Delete. The result is it causes issues if we try to run terratest or TF_ACC=1, where the zone settings are deleted (reverted) at the end of the tests.

The tests have been updated to read in the singleZoneSettings.

[tootelldels]

Fixes:

• https://github.com/terraform-providers/terraform-provider-cloudflare/issues/531

[jacobbednarz]

@tootelldels is this ready for review now? I'm unsure what the status is from your side.

[tootedom]

Hi @jacobbednarz ,

All ready from my side. Please review away.

Cheers
/dom

[jacobbednarz]

LGTM, thanks!