commit: no longer allow empty commit with the 'force' argument (API)
The new way to allow empty commit is to temporarily set the
'ui.allowemptycommit' config option.
allowemptyback = repo.ui.backupconfig('ui', 'allowemptycommit')
try:
repo.ui.setconfig('ui', 'allowemptycommit', True)
repo.commit(...)
finally:
repo.ui.restoreconfig(allowemptyback)
All known uses of force for allowing empty commits have been removed, so let's
remove it from the allowemptycommits condition.