tests/test-gendoc-sv.t

streamclone: move wire protocol status code from wireproto command

This consolidates the code for the streaming clone wire protocol format
into streamclone.py. It also eliminates a generator wrapper, which might
make streaming clones slightly faster.

Differential Revision: https://phab.mercurial-scm.org/D1754

#require docutils gettext

  $ $TESTDIR/check-gendoc sv
  checking for parse errors