(CFACT-142) Fix fqdn fact not being initialized properly.

The fqdn fact was only resolving if the qualified domain could be looked
up.  If the lookup failed, we used to fall back to simply doing the
hostname + domain.

That fallback was incorrectly removed during a refactoring.  This commit
simply adds it back.
Merge pull request #190 from peterhuene/cfact/142

(CFACT-142) Fix fqdn fact not being initialized properly.