We should re-run host_prep_tasks as part of the minor update, to make
sure the host is ready for starting the updated containers. The right
place for them is between update tasks and deployment tasks.
This is important in case we deliver changes to host_prep_tasks during
minor update, or if update_tasks do something that would partially
undo the host preparation, e.g. clear/delete some directories on the
host to get rid of previous state.
Change-Id: Ic0a905a8c4691cbe75113131bd84e8a39dea046d
Related-Bug: #1776206
416b35f4c3