If when you say 'out of date' the old branches are strict ancestors then you don't really have any merge issues.
If you just want to make your current branch into the master branch on your remote repository you can just do:
git push origin HEAD:master
Edit: from one of your comments it sounds like you don't have all of the changes from remote master in your current branch, though, so you may need to merge them in before pushing successfully:
git fetch
git merge origin/master
You can then delete you local branches. delete with a small -d
is safe in that it only deletes branches that are ancestors of your current branch.
git branch -d master
git branch -d refresh.
If it bothers you that your local branch isn't called master you can now do:
git checkout -b master
git branch -d auth_upgrade