streamclone: pass narrowing related info in _walkstreamfiles()
This patch build a matcher using the include and exclude arguments we have in
generatev2() and pass that matcher into _walkstreamfiles(). This will help us
in filtering files we stream depending on the includes and excludes passed in
by the user.
Differential Revision: https://phab.mercurial-scm.org/D4851
ERROR: FIXME: This is a known failure of filelog.size for data starting with \1\n
OK.