imap: Use mailbox_exists() to find out if namespace prefix is selectable or not. mailbox_list_mailbox() should be treated as an internal function, since ACLs don't apply to it.
imap: Use mailbox_exists() to find out if namespace prefix is selectable or not.
mailbox_list_mailbox() should be treated as an internal function, since
ACLs don't apply to it.

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