Reset forked repo to match original (upstream) for a pull request http://scribu.net/blog/resetting-your-github-fork.html

reset repo

git clone https://github.com/lardcanoe/repo.git
cd repo
git remote add upstream https://github.com/repo/repo.git
git pull --rebase upstream
git pull --rebase upstream devel
git checkout -b repo_branch origin
git add new_file
git commit
git push origin repo_branch