Missing image-del func in test_create_delete_image

* Test Case test_create_delete_image is missing image-delete
  functionality and the image is left undeleted after running this
  test. So adding image-delete functionality to test the delete
  function.

* This is a smoke test that tests create & delete image functionality.

Change-Id: I14fa4e65b83791f3effc2ca5694d363e2b7f09bd
Merge "Missing image-del func in test_create_delete_image"