Allow only temporary zone updates without making them permanent

[Lefteris Tsintjelis]

On 26/6/2019 21:13, Tony Finch wrote:
> It will rewrite the
> zone file from scratch when it merges in the journal, which is what would
> cause the change of ownership.

That makes perfect sense, but I was still shocked when I first saw it
specially to a file owned by root. This is the part that surprised me
and worried me the most! I was under the impression that after start up,
named would switch to the user configured to do so and it will no longer
be able to access or change other files but its' own.

Lefteris