lib-storage: Fixed crash if shared namespace had subscriptions=yes
lib-storage: Fixed crash if shared namespace had subscriptions=yes

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