OVH: fix ovh integration tests for release_candidate_v5

[masterzen]

What?

This makes the integration tests pass for the OVH provider on top of the release_candidate_v5 work.

Why?

TXT record parsing seems to have changed, and TXT records where quoted again when parsed.

[masterzen]

While this fixes some of the integration tests, some are still failing:

=== RUN   TestDNSProviders/dnscontroltest.ovh/27:complex_TXT:a_0-byte_TXT
    helpers_integration_test.go:255: OVHcloud API error (status code 400): Client::BadRequest: "{'target': ['Invalid input.']}" (X-OVH-Query-Id: EU.ext-4.6a4ea284.3587060.75b31d3c7614bc9e33a63aea301fdb8e)
=== RUN   TestDNSProviders/dnscontroltest.ovh/97:structured_TXT_as_native_records:Create_native_OVH_records
    helpers_integration_test.go:255: OVHcloud API error (status code 400): Client::BadRequest: "Invalid subdomain: dkim" (X-OVH-Query-Id: EU.ext-3.6a4ea343.1196486.1857a3461e2a5378c77f82354f6a3541)

I need to have a deeper look.