Fix README.rst, add a check for it to fit PyPI rules

README.rst doesn't appear right on PyPI currently. This commit fixes the
issue and expands "docs" environment in tox.ini to use readme tool [0]
to verify that README.rst is good for PyPI.

[0] https://github.com/pypa/readme

Change-Id: I6025bb6c661d8a4a7cd9802a1298928662278f2d

README.rst

@@ -355,7 +355,7 @@ with - as well as a consumption argument.
 Constructing Legacy Client objects
 ----------------------------------
 
-If all you want to do is get a Client object from a python-*client library,
+If all you want to do is get a Client object from a python-\*client library,
 and you want it to do all the normal things related to clouds.yaml, `OS_`
 environment variables, a helper function is provided. The following
 will get you a fully configured `novaclient` instance.

tox.ini

@@ -21,7 +21,12 @@ commands = {posargs}
 commands = python setup.py test --coverage --coverage-package-name=os_client_config --testr-args='{posargs}'
 
 [testenv:docs]
-commands = python setup.py build_sphinx
+deps =
+    {[testenv]deps}
+    readme
+commands =
+    python setup.py build_sphinx
+    python setup.py check -r -s
 
 [flake8]
 # H803 skipped on purpose per list discussion.