If mail_get_stream() succeeds but mail_get_*_size() fails, we didn't reference the stream so we must not unreference it later either.
If mail_get_stream() succeeds but mail_get_*_size() fails, we didn't
reference the stream so we must not unreference it later either.

Distrotech/dovecot,Distrotech/dovecot,Distrotech/dovecot,Distrotech/dovecot,Distrotech/dovecot