Moves negative tests to test_images_oneserver_negative

Segregation of negative tests into appropriate negative files.

This change just moves negative tests from
api/compute/images/test_images_oneserver to
api/compute/images/test_images_oneserver_negative

Change-Id: I98434e6042784ad344d626c2be5ad84cadd5c737
Merge "Moves negative tests to test_images_oneserver_negative"