qttools: Remove unused variables/configurations
qttools: Remove unused variables/configurations

Grepped around in sources of qttools and qtbase: there is not a single hint
that these settings cause any effect.
For the clang_config.. variables [1] was found: Seems the variables set were
removed a while back.

[1] https://code.qt.io/cgit/qt/qttools.git/commit/?id=e181ec2c20ede6b878187f3123d190e8b952deb1

Signed-off-by: Andreas Müller <d72a15aaaca3a7afa855175c72dc8d2e05931e32@gmail.com>

schnitzeltony/meta-qt5,meta-qt5/meta-qt5,meta-qt5/meta-qt5,schnitzeltony/meta-qt5