strip: ignore -n (issue3326) (BC)

-n could be confused for --dry-run by foolhardy users, resulting in
 permanent data loss.

As leaving a backup when none was requested is significantly less
disastrous, the short option is silently ignored. Old scripts continue
to work, users only get lightly burned.

hgext/mq.py

@@ -2762,8 +2762,9 b' def save(ui, repo, **opts):'
           ('b', 'backup', None, _('bundle only changesets with local revision'
                                   ' number greater than REV which are not'
                                   ' descendants of REV (DEPRECATED)')),
-          ('n', 'no-backup', None, _('no backups')),
+          ('', 'no-backup', None, _('no backups')),
           ('', 'nobackup', None, _('no backups (DEPRECATED)')),
+          ('n', '', None, _('ignored  (DEPRECATED)')),
           ('k', 'keep', None, _("do not modify working copy during strip"))],
           _('hg strip [-k] [-f] [-n] REV...'))
 def strip(ui, repo, *revs, **opts):