Fix ipa-ccache-sweeper activation timer and clean up service file
Added OnActiveSec=12h to start the timer cycle because OnUnitActiveSec setting alone never triggers the timer after boot as there has not been transition between active and inactive state.
Removed [Install] section from sweeper.service as it is not needed
Fixes: https://pagure.io/freeipa/issue/9231
Signed-off-by: Jesse Sandberg <jesse.sandberg@netcode.fi>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>