Fix broken smoke tests

-Updated test_create_export_task
*Moved create_image_via_task method call to setup class
-Updated test_delete_image
*Updated setup class to use create_image_via_task
-Updated test_update_image
*Removed smoke tag
*Updated setup calss to use create_new_image
*Removed visibility references

Change-Id: Ibc87c7eb3681a7aaaef5f4269bbb118058cdf27c