remote-hg: fix new branch creation
When a user creates a new branch with git:
% git checkout -b branches/devel
and then pushes this branch
% git push origin branches/devel
which is the way to push new mercurial branches, we do want to
create a branch, but the command would fail without newbranch=True.
This only matters when force_push=False, but setting newbranch=True
unconditionally does not hurt.
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>