Reviewed by Kenneth Rohde Christiansen.

The dependencies were a bit wrong, so we ended up not generating
forwarding headers for qwebkitversion.h and qwebkitglobal.h

The forwardning headers are now the only targets depending on the
real headers. All other targets either depend on the generated
class headers, or the forwarding headers.

* Api/DerivedSources.pro:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@55515 268f45cc-cd09-0410-ab3c-d52691b4dbfc