Adding unit test cases for Volume management rest endpoints.
Adding unit test cases for Volume management rest endpoints.

Signed-off-by: Imran Pochi <d6d3ccaa384a65532061e26836842adc48d43df4@infracloud.io>

pault84/openstorage,pault84/openstorage,libopenstorage/openstorage,libopenstorage/openstorage,libopenstorage/openstorage,pault84/openstorage