Fix bullet list format in README.rst

Change-Id: I72664bdc2acc8507d2ca262661317780f9d0c090
Ignore publish-docs directory

Ignore publish-docs directory. This is the directory used by
openstack-doc-test to copy draft documents to.

blueprint draft-docs-on-docs-draft

Change-Id: Ia4bff14e89f632accee8485ec2644a82317b952a