Switch to etherpad-lite 1.7.0 in production prior to the PTG. This
version brings a couple more security fixes since 1.6.6 and also
fixes the bullet list authorship misattribution bug. See
https://github.com/ether/etherpad-lite/blob/1.7.0/CHANGELOG.md for a
summary of changes. The version of NodeJS we're using now should
meet the minimum requirements (but will need to be updated prior to
the next etherpad-lite release). This version is the one currently
served from etherpad-dev.openstack.org and can be tested there as
desired.
Change-Id: If52d1b1c3dc33da56133ccb5e6adf33ebd3d2428