tox: Remove dead settings/targets
tox: Remove dead settings/targets

The sdist target is useless given that releases are automated.
Similarly, the '[testenv] install_command' uses the default value and is
therefore not required. Finally, some other things were slightly off or
otherwise annoying and can be fixed.

Change-Id: Ia029aba9ee5bc79cf39043a5fcaf9463aa1518f7
Signed-off-by: Stephen Finucane <4725dc7f3632bf126d9fbdc30c347e91e8d2fe16@redhat.com>

openstack-infra/git-review