Fix releasenotes index
Fix releasenotes index

Add new line at end so that translations work.

See
http://logs.openstack.org/38/390038/1/check/gate-neutron-vpnaas-releasenotes/e1e19ce/console.html#_2016-10-23_06_05_56_418542
for failure.

Change-Id: I06a35b8c710841de111287d40c68f00867c4654d

openstack/neutron-vpnaas,openstack/neutron-vpnaas