Clean up unused QDebug/baloodebug.h includes

Summary: The code does not use qDebug(), qWarning() or similar, so remove it.

Test Plan:
make
ctest

Reviewers: Baloo, Frameworks, broulik, ngraham

Reviewed By: Baloo, broulik, ngraham

Subscribers: kde-frameworks-devel

Tags: Frameworks, Baloo

Differential Revision: https://phabricator.kde.org/D16043