stream: in v3, skip the "size" fast path if the entries as some unknown size
We are about to prefetch size during the lock less in the v3 case. So we need to
avoid trying to use that prefetched size when it is not available.
See next changeset for the motivation.
#require docutils gettext
$ $TESTDIR/check-gendoc de
checking for parse errors
Die Dateien werden dem Projektarchiv beim n\xc3\xa4chsten \xc3\x9cbernehmen (commit) hinzugef\xc3\xbcgt. Um dies vorher r\xc3\xbcckg\xc3\xa4ngig zu machen, siehe:hg:`forget`. (esc)
warning: please have a space before :hg: