In the review of the initial create of the `to-stein` document [1]
some shortcomings were identified that this patch tried to address:
* making it clear that upgrading to extracted placement doesn't have to
be the same time as upgrading to stein
* stop using contractions
* clarify several points. In some cases this means being more
general, in others more specific
* Add some thoughts on verification
* Change the verb "copy" to "move" in a few places. This was done
to help make sure that nova will not remain configured to use
its own placement, which would be very messy.
[1] I32b22d75400c7f7b428ed3d48ac928584071ed29
Change-Id: I722275eba2d17e0751a9a4ccfc58a8e7ede864da
5d0f875c97