We now use the project openstack/ironic-tempest-plugin to store our
tempest plugin. All content from the ironic_tempest_plugin/ directory
has been ported to that project.
We no longer want to have the plugin content stored here so we delete
it.
Remove check in tools/flake8wrap.sh that prevented changes to the
ironic_tempest_plugin/ directory.
Change-Id: I700bd7b71472fa91f6bc02aebc055584df08e0ef