Some minor things after looking at these parts.
The dib-run-parts element doesn't do any of the copying any more, so
these comments are wrong.
The reason for the multiple mounts in the bind mount was non-obvious
to modern eyes (as util-linux has handled this for some time).
Formatting fix for the rst
Change-Id: Idb4c9ff32c49aced2c68a5c905bf7a8b2832a5a2