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
Fix the invalid create volume response body and add the test

Change-Id: I56777a602913ccd3f260cc714042bfb04b206a1e
Merge pull request #116 from ajiang38740/sl_portable_storage_volume_create_delete

Add  create and delete to Jumpgate volume API