packaging: configuration cleanups

- install isouploader.conf with 0640 access mode
- avoid to install hidden empty files for creating an empty
  configuration directory

Change-Id: I015e614821c21715c99af0abe398687bb2e39422
Bug-Url: https://bugzilla.redhat.com/1058807
Signed-off-by: Sandro Bonazzola <sbonazzo@redhat.com>