Added openSUSE support. Refs #56.
Add install deps for openSUSE.
Fix key value.
Non interactive add repo.
Add install tests `tearDown()` support for Suse OS family.
Allow errno 4 exit codes from zypper to be ignored.
Skip install test if there's no `tearDown()` support.
Suse packages needs some help to properly un-install.
Suse packages provide `salt-syndic` as a separate package.
Add `salt-syndic` to the tearDown packages.
Packages are now properly cleaned up for Suse distro's on install tests.