reset prereqs status on clean.sh

when running a clean, we should really reset the prereq status as
well, as this should start us back from zeroish.

Change-Id: I5fae151ab13bcf7fb82feb1e91eed19e0215dc59
Create stack_domain_admin user

Create an additional service user for Heat, which is a domain admin
for the stack_user_domain - this is necessary since the normal service
user cannot manage the projects/users in the stack_user_domain when
keystone is configured to use the v3cloudsample policy (such as in
gate integration tests).

Change-Id: If59c11a74145b9bd02f78a7e0882afe1b0a72e40
remove sysstat & pidstat

dstat is far cleaner for getting results out of the environment,
and covers the bulk of our use cases for sysstat and pidstat with
a much better ui.

devstack is allowed to be opinionated, so become opinionated here.

Change-Id: I21ec96339dcd704098512fdafd896738f352962d
Merge "reset prereqs status on clean.sh"
Merge "remove sysstat & pidstat"
Merge "Create stack_domain_admin user"