If prefix.INBOX has children and we're listing under prefix.%, don't drop the prefix.
If prefix.INBOX has children and we're listing under prefix.%, don't drop
the prefix.

--HG--
branch : HEAD

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