Add git-upstream as new project to stackforge

This patch adds the config needed to create and maintain git-upstream
in stackforge.

git-upstream is an open source Python application that can be used to
keep in sync with upstream open source projects, mainly OpenStack.

The main usecase for this tool is for people who are doing active
contributions to repositories that are mirrors of OpenStack
repositories, with the intention that most of those contributions
will be submitted to review.openstack.org at some point.
If you are running a public cloud based on OpenStack, having local
changes needed to use it in your environment, you can use
git-upstream to stay up to date with the upstream master in a easier
way (with respect to using raw git commands).

git-upstream provides new git subcommands to support rebasing of
local-carried patches on top of upstream repositories. It provides
commands to ease the use of git for who needs to integrate big
upstream projects in their environment.
The operations are performed using Git commands.

See also:
 * https://github.com/dguerri/git-upstream
 * https://pypi.python.org/pypi/git-upstream

Change-Id: I16f71cbe7178b9e98bed2ee0a9c905b5ee9bc395
Merge "Add git-upstream as new project to stackforge"