fix auth for newer ODL versions

Since oxygen we need to add also "-p karaf" argument when
starting karaf and because we are not using older versions
anymore we can remove the if condition and use new authentication
by default.

Change-Id: I458fa35b7f26222dd5562349e6859844bfb7d05f
Signed-off-by: Michal Cmarada <mcmarada@cisco.com>