Previously, Tempest's default for scheduler_available_filters was
'all'. This was different from Nova's default enabled_filters, which
does *not* include all possible filters available in Nova. Thus, in a
deployment where both options were kept at their default value,
Tempest's is_scheduler_filter_enabled() would return True for all
filters, even if those filters weren't enabled in Nova. In addition,
the 'available' wording could be made clearer. This patch deprecates
scheduler_available_filters, replacing it with
scheduler_enabled_filters. The latter has its default value set to
Nova's enabled_filters default.
Related-bug: 1628443
Change-Id: I5c87865dc650d383ee006d36b6d52cdd90577ab9
595ae16987