Cope with Wales Office accidental org creation

Wales office also has Swyddfa Cymru, which is the same org title.
Its title should be said to be equal, even though it's a different
string.
Fix org parenting issues

* sites are correctly assigned to orgs which themselves belong to departments
* orgs do not get a parent prefix (UK Atomic Energy Authority org.abbr is now
    'ukaea' rather than 'bis_ukaea'
* sites retain their full redirector abbreviations for compatibility
Merge pull request #41 from alphagov/org-parenting-issues

Organisation/site parenting issues