hostnamectl: allow trailing dot on fqdn

hostnamectl: allow trailing dot on fqdn

When the user requests to set hostname, and we are setting both
pretty and static hostnames, and the name is a valid FQDN, we
use it as the static hostname, and unset the pretty hostname.
The change is that a FQDN with a trailing dot is accepted and ignored.

https://bugzilla.redhat.com/show_bug.cgi?id=1238246

Lowercasing of the static name is not done anymore.

$ hostnamectl set-hostname Foobar.
=> static is "Foobar", pretty is "Foobar."
$ hostnamectl set-hostname Foobar.org.
=> static is "Foobar.org", pretty is unset
$ hostnamectl set-hostname Foobar.org..
=> static is "Foobar.org", pretty is "Foobar.org.."