Description of problem:

After upgrade from OSP 7 to OSP 8, there are some parameters which were set in environment files using `parameters` in OSP 7 but are set using `parameter_defaults` in OSP 8 (e.g. storage related parameters like CinderEnableRbdBackend). Those parameters will not use the new `parameter_defaults` values in the environment files passed on the command line, but will continue using to the old `parameters` values used when deploying OSP 7, because `parameters` take priority over `parameter_defaults`.

This is only issue during upgrades, new deployments work as-is.

Workaround is possible -- if discovered that some `parameter_defaults` values are not taken into account because the overcloud stack already had them set via `parameters` in the past, craft a custom environment file that will set the new desired values via `parameters` again, instead of the new implicit way via `parameter_defaults`.