General test cleanup
General test cleanup

- removal of unnecessary code
- update usage of create_image_enabled in image test
- rewriting image metadata tests
- fixing test_images skip
- add exceptions.ComputeFault
- fix server actions teardown
- fixing rebuild name verification
- rewriting server metadata tests

Change-Id: I03f29d864c456cbc78ca6d6dae25cacbcdf2b0d9

cneill/tempest-lib,mtreinish/tempest-lib,JioCloud/tempest-lib,afaheem88/tempest-lib,sorenh/tempest-lib,varunarya10/tempest-lib