Changes the xml:id for Obj Storage verification in install

A unique ID should force Disqus to start a new thread for the
havana install guide commenting.

backport: havana
Change-Id: I19774d3d75f97585d1e489dc3142c97aebcdb9be
Closes-bug: 1250288
(cherry picked from commit 858d3c5458555d9a3c7a6f465a1e0295abf1cadd)