Added a CreateSlice to test_CreateSliverWorkflow_fail_notexist on the philosophy that we are testing what happens when you operate on a _sliver_ which does not exist.  Failing when the slice doesn't exist at the SA just isn't helpful.
Added a CreateSlice to test_CreateSliverWorkflow_fail_notexist on the philosophy that we are testing what happens when you operate on a _sliver_ which does not exist.  Failing when the slice doesn't exist at the SA just isn't helpful.

plantigrade/geni-tools,tcmitchell/geni-tools,GENI-NSF/gram,ahelsing/geni-tools,GENI-NSF/gram,GENI-NSF/gram,plantigrade/geni-tools,ahelsing/geni-tools,tcmitchell/geni-tools