sub org fixes
• fix mulitple parent org logo display with varying logo heights (i.e. mod and home office)
• move content_tag h1 inside unless sub-org as is always emtpy for sub orgs
• update sub org h2 to h1
fix failing test looking for h2 to h1
Merge pull request #628 from alphagov/sub-org-fixes

sub org fixes

https://www.pivotaltracker.com/story/show/49871461