RDF Errors

This issue comes from #1451864: Notice: Undefined index. Seems to be two separate issues so thought it would be best to separate them.

I'm getting the following errors from a fairly clean install:

Notice: Undefined variable: rdf_header in include() (line 1 of /sites/all/themes/mothership/mothership/templates/html.tpl.php).
Notice: Undefined variable: rdf_profile in include() (line 7 of/sites/all/themes/mothership/mothership/templates/html.tpl.php).

On looking into it the variables aren't defined anywhere at all so I'm not sure what they're meant to do. All this patch does is revert them to the values in the default html.tpl.php.