Revert f3d15aa8, kdeclarative include paths

This patch is wrong, the correct solution was committed by Marco with
fd2cc8aa a little less than two hours before.

Benjamin, this was discussed on the frameworks-devel list, your patch
essentially reverts Marco's earlier patch, and breaks the
plasma-frameworks build, *right after* Marco has fixed it (renamed
libkdeclarative dir to kdeclarative, which also corrects the include
paths for clean builds).

Could you:
- Check if it now works for you as well?
- Check the mailinglist and existing discussion about this kind changes
  before committing, and if you push after rebasing, maybe quickly check
  if anything related happened in between? (This seems to be the case
  here, bad timing, but also a lack of communication.)

I've reverted it for now (and I hope you're OK with that), since I've
this change on my disk anyway.

CCMAIL:benjamin.port@ben2367.fr
CCMAIL:kde-frameworks-devel@kde.org