add upgrade testing expectation

This was part of the original QA proposal for project requirements,
however when we lost the post integration section it was lost. We
should bring back the expectation of upgrade testing, as one of
the top community concerns by operators it the ability to upgrade
their clouds from one release to the next.

Change-Id: Ie01d2a8b27e7cf9a0ec924c1d11d748af364929e
Merge "add upgrade testing expectation"