Change PyPI name to ironic-lib and clean up setup.cfg
Change PyPI name to ironic-lib and clean up setup.cfg

Our project is called ironic-lib, no point in publishing it as ironic_lib.
It's also inconsistent with tempest-lib.

This patch also removes unneeded elements from setup.cfg and switches
to postversioning.

Change-Id: I29c0f384fb8869ce3e28dedf0272fcc2e766fc26

NaohiroTamura/ironic-lib,citrix-openstack-build/ironic-lib,openstack/ironic-lib