This changeset fixes how some digitalocean dns records were getting
parsed. In particular, it allows for understanding "@" as shorthand for
the domain itself, preventing terraform from suggesting changes that
wouldn't have any actual effect. This changeset also adds a trailing "."
to certain record types which are required to be submitted with a
trailing dot, but which digitalocean does not return with a trailing
dot, again preventing changes that wouldn't have an effect.
Tests have been added for the above, and with just adding the tests, the
current code is failing, as it is handling some records(e.g. MX)
incorrectly
