changegroup: replace getlocalchangegroupraw with makestream
As part of reducing the number of changegroup creation apis, let's replace calls
to getlocalchangegroupraw with calls to makestream. Aside from one case of
checking if there are no outgoing commits and returning None, this is pretty
much a drop in replacement.
Differential Revision: https://phab.mercurial-scm.org/D666
#require docutils gettext
$ $TESTDIR/check-gendoc it
checking for parse errors