utils: fixing optional parameters

Adding names for optional parameters so we do not need to
depend on ordering.

Change-Id: I2649a7d3a8a1e98268356833ad9bc6a4eaed1715
Signed-off-by: pkliczewski <piotr.kliczewski@gmail.com>
Reviewed-on: http://gerrit.ovirt.org/28857
Reviewed-by: Nir Soffer <nsoffer@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>