qt4: fix deps in libQtWebkit.la and QtWebKit.pc

qt4: fix deps in libQtWebkit.la and QtWebKit.pc

* Both files contain -L../../WebCore/release -L../../JavaScriptCore/release -lwebcore -ljscore
* These paths and libs don't get installed.
* When building a shared lib with libtool, that links
  with libQtWebKit, libtool adds these unneeded parameters
  to the linker command-line, thus linking fails.

(From OE-Core rev: 4c41a3204ef72f53813ddc86fe525fa9c6714daa)

Signed-off-by: Andreas Oberritter <obi@opendreambox.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>