Avoid installing log categorie file to KDE_INSTALL_CONFDIR
Summary: Since we depend here on ECM > 5.61 we don't need to install the categorie file to KDE_INSTALL_CONFDIR
Reviewers: ivan, cgiboudeaux
Reviewed By: cgiboudeaux
Subscribers: kde-frameworks-devel
Tags: Frameworks
Differential Revision: https://phabricator.kde.org/D23855