lib-storage: If trying to copy a message into already deleted mailbox, don't crash.
lib-storage: If trying to copy a message into already deleted mailbox, don't crash.

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