add LNST regression tests

This commit adds LNST regression tests that we have had in a separate
git repository until now.
The test can now be run locally as well:
cd regression-tests
./run-git-test.sh

The regression-tests/env/ directory contains a configuration file that
will be used, however if you have local configuration in your ~/.lnst
directory it will override the env/ configuration.

Signed-off-by: Ondrej Lichtner <olichtne@redhat.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>