This change allows us identifying a set of parameters which should
not been passed in the upgrade prepare or upgrade converge steps.
As it is now, it is mostly intended to block the converge step
if the FFU parameters (Stein registry parameters) were left in
the environment files before running the converge step, however
it will allow blocking the upgrade prepare in the case that some
deprecated or not recommended parameter is provided in the templates.
The way how it works is by converting every single yaml passed in
the environment files into a list of keys (only for the
parameters_default so far), then it will try to intersect the list
of forbidden parameters with the list of keys. If there is a match
an exception will be raised showing those parameters:
ERROR openstack [-] The following parameters should be removed from
the environment files: