Add Apache License Content in index.rst
Add Apache License Content in index.rst

1. What is the problem?
Apache License 2.0 is lack in ./releasenotes/source/index.rst

2. What is the solution to the problem?
Add Apache License 2.0 Content which is necessary
for ./releasenotes/source/index.rst.

3. What the features need to be implemented to the Tricircle to realize the solution?
No need

Change-Id: I4bde1947cb66da9a4c69bb10d6b4af6604012411

openstack/tricircle,stackforge/tricircle,openstack/tricircle,stackforge/tricircle