* spot/twaalgos/emptiness.hh (emptiness_check_instantiator): rename
min_acceptance_conditions and max_acceptance_conditions to
min_sets and max_sets.
* spot/twaalgos/emptiness.cc, python/ajax/spotcgi.in,
tests/core/ikwiad.cc, tests/core/emptchk.cc, tests/core/randtgba.cc:
Adjust.
* doc/org/upgrade2.org, NEWS: Mention the change.