For the nsxv plugin when using the dvs features, we should not
repeat the dvs name information unless required, as the dvs moref
may be set as part of the nsxv configuration. And if the dvs moref
is set in the nsxv configuration then, we should use that to
initialize DvsManager.
Change-Id: Ibd81190aa91f255237c76f93e0fc15ab2659d6c7