show FQDN first in /etc/hosts (closes: #3521)

[anarcat]

The hosts(5) manpage clearly states that the first entry is the
"canonical name", or FQDN (Fully-Qualified Domain Name):

IP_address canonical_hostname [aliases...]

By using the alias as a first entry, hostname -f does not return the
correct domain which breaks all sorts of unrelated functionality (it
has impact over email server configuration, for example).

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[anarcat]

I probably will get hit over the head on this, but I haven't been able to test this locally - I'm hoping the CI will do that work for me considering how small this change is. :) i'm also fighting with email/greylisting/whoknowswhat to clear that annoying CLA requirement.. sorry for the trouble.

[anarcat]

against my better judgment and with heaps of patience, i signed the CLA.

[anarcat]

no idea what else i'm supposed to do here. i'm lost in a maze of CI and bureaucracy. help!

[Atoms]

ci check this

[Atoms]

/lgtm

[Atoms]

/approve

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