Add release notes page for 17.1.0 & 17.2.0

This commit adds new index pages for 17.1.0 and 17.2.0
releases.

Currently there is no index page for 17.1.0
and 17.2.0 on release notes page
- https://docs.openstack.org/releasenotes/tempest/

Change-Id: If405d16b77171ebaabc39547a75c6da3b4234197
diff --git a/releasenotes/source/v17.2.0.rst b/releasenotes/source/v17.2.0.rst
new file mode 100644
index 0000000..8566ae4
--- /dev/null
+++ b/releasenotes/source/v17.2.0.rst
@@ -0,0 +1,6 @@
+=====================
+v17.2.0 Release Notes
+=====================
+
+.. release-notes:: 17.2.0 Release Notes
+   :version: 17.2.0