Fix python bindings compilation after 7af93dd23873d0b9cdbac192949e7e5114940aa6
Explicitely set LIBRARY_OUTPUT_DIRECTORY for the python module
Differential Revision: https://phabricator.kde.org/D7677
CCMAIL: release-team@kde.org
(cherry picked from commit 8b4033f16c2ae07c57364cde62c21bd0e75539c3)