Add pypi download + version badges into README.rst

This commit adds pypi download and version badges into README.rst.
With these badges, users can know the latest version and download
statistics.

Change-Id: Ib9ec24ea82d478e44160a6d7f381d8c43a2dcbf5
diff --git a/README.rst b/README.rst
index c859ddd..7da83cd 100644
--- a/README.rst
+++ b/README.rst
@@ -1,6 +1,14 @@
 Tempest - The OpenStack Integration Test Suite
 ==============================================
 
+.. image:: https://img.shields.io/pypi/v/tempest.svg
+    :target: https://pypi.python.org/pypi/tempest/
+    :alt: Latest Version
+
+.. image:: https://img.shields.io/pypi/dm/tempest.svg
+    :target: https://pypi.python.org/pypi/tempest/
+    :alt: Downloads
+
 This is a set of integration tests to be run against a live OpenStack
 cluster. Tempest has batteries of tests for OpenStack API validation,
 Scenarios, and other specific tests useful in validating an OpenStack