Add  create and delete to Jumpgate volume API

    1. Support SL portable storage create operation via jumpdate
    2. Support SL portable storage delete operation via jumpdate
    3. Add unittest coverage for jumpgate volume create/delete

Change-Id: I9cd6acb0832279fdfa5080e728ecaef9ac9de638
Actually, I'm more worried about parallel volume creates under the same tenant, as this logic looks like its just grabbing the first portable storage that has "isActive" == 1.  In this situation, simultaneous creates would both return back the same volume-id.  Is it possible to utilize the "name" value in that search?  Note this means we may want to insert a small random number if the Openstack volume-name parameter was left empty.