lib-index: Avoid assert-crashing when syncing an old "keyword reset" from transaction log.
lib-index: Avoid assert-crashing when syncing an old "keyword reset" from transaction log.

jwm/dovecot-notmuch,jkerihuel/dovecot,jkerihuel/dovecot,jkerihuel/dovecot,jwm/dovecot-notmuch,jkerihuel/dovecot,jwm/dovecot-notmuch,jwm/dovecot-notmuch,jkerihuel/dovecot,jwm/dovecot-notmuch