Git 2.0 the default behavior will be to only push the current branch checked out. The option is currently a setting called simple for option push.default.
So you can set this new (in my opinion better) default behavior right now.
$ git config --global push.default simple
and that’s it. Just in case you want to use that. The old default, that pushed everything at once just in case you want to go back was matching, instead of simple.