test: Fix use of TEST_DATA by multiple unix users
test: Fix use of TEST_DATA by multiple unix users

The images downloaded should be readable by anyone, and not be
writable. People who want to share $TEST_DATA between multiple
users can set it up so that the directory can be written to by
those users. But this pull request fixes it so the downloaded
images are sharable by default.

In addition we account for the idea that a qcow image may be there
but the symlink to $TEST_DATA may be missing.

Closes #5237
Reviewed-by: Dominik Perpeet <f7830b2723a5db4fc185058b06cfab4b89a38da9@redhat.com>

vanloswang/cockpit,dperpeet/cockpit,deryni/cockpit,deryni/cockpit,larskarlitski/cockpit,petervo/cockpit,cockpituous/cockpit,Scribery/cockpit,martinpitt/cockpit,sgallagher/cockpit,SotolitoLabs/cockpit,arilivigni/cockpit,michalskrivanek/cockpit,vanloswang/cockpit,stefwalter/cockpit,deryni/cockpit,andreasn/cockpit,moraleslazaro/cockpit,arilivigni/cockpit,michalskrivanek/cockpit,Scribery/cockpit,martinpitt/cockpit,arilivigni/cockpit,mareklibra/cockpit,harishanand95/cockpit,harishanand95/cockpit,deryni/cockpit,deryni/cockpit,arilivigni/cockpit,mareklibra/cockpit,dperpeet/cockpit,larsu/cockpit,andreasn/cockpit,harishanand95/cockpit,petervo/cockpit,vanloswang/cockpit,sgallagher/cockpit,xhad/cockpit,larskarlitski/cockpit,xhad/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,larsu/cockpit,cockpituous/cockpit,dperpeet/cockpit,larskarlitski/cockpit,larskarlitski/cockpit,mareklibra/cockpit,andreasn/cockpit,moraleslazaro/cockpit,stefwalter/cockpit,dperpeet/cockpit,andreasn/cockpit,moraleslazaro/cockpit,mareklibra/cockpit,michalskrivanek/cockpit,dperpeet/cockpit,xhad/cockpit,Scribery/cockpit,garrett/cockpit,larskarlitski/cockpit,cockpit-project/cockpit,petervo/cockpit,moraleslazaro/cockpit,michalskrivanek/cockpit,sgallagher/cockpit,stefwalter/cockpit,petervo/cockpit,michalskrivanek/cockpit,mareklibra/cockpit,garrett/cockpit,mareklibra/cockpit,stefwalter/cockpit,sgallagher/cockpit,cockpituous/cockpit,harishanand95/cockpit,dperpeet/cockpit,cockpit-project/cockpit,mareklibra/cockpit,SotolitoLabs/cockpit,michalskrivanek/cockpit,petervo/cockpit,xhad/cockpit,arilivigni/cockpit,sgallagher/cockpit,cockpituous/cockpit,harishanand95/cockpit,SotolitoLabs/cockpit,mvollmer/cockpit,martinpitt/cockpit,sgallagher/cockpit,vanloswang/cockpit,mvollmer/cockpit,SotolitoLabs/cockpit,arilivigni/cockpit,cockpituous/cockpit,SotolitoLabs/cockpit,SotolitoLabs/cockpit,garrett/cockpit,michalskrivanek/cockpit,harishanand95/cockpit,xhad/cockpit,garrett/cockpit,xhad/cockpit,dperpeet/cockpit,mvollmer/cockpit,larskarlitski/cockpit,cockpit-project/cockpit,deryni/cockpit,harishanand95/cockpit,moraleslazaro/cockpit,larsu/cockpit,vanloswang/cockpit,andreasn/cockpit,Scribery/cockpit,stefwalter/cockpit,petervo/cockpit,deryni/cockpit,martinpitt/cockpit,Scribery/cockpit,stefwalter/cockpit,stefwalter/cockpit,Scribery/cockpit,andreasn/cockpit,larsu/cockpit,Scribery/cockpit,garrett/cockpit,xhad/cockpit,sgallagher/cockpit,SotolitoLabs/cockpit,cockpit-project/cockpit,larskarlitski/cockpit,mvollmer/cockpit,vanloswang/cockpit,martinpitt/cockpit,mvollmer/cockpit,vanloswang/cockpit,larsu/cockpit,arilivigni/cockpit,petervo/cockpit,larsu/cockpit,andreasn/cockpit,cockpituous/cockpit