Fixes the "Warning! PATH is not properly" warning because of PATH order

The defaults add the rvm path after the original path, making the
```
Warning! PATH is not properly set up, '/Users/mikal/.rvm/gems/ruby-2.1.2/bin' is not at first place,
         usually this is caused by shell initialization files - check them for 'PATH=...' entries,
         it might also help to re-add RVM to your dotfiles: 'rvm get stable --auto-dotfiles',
         to fix temporarily in this shell session run: 'rvm use ruby-2.1.2'.
```
spawn by default.

This fixes it. Other than that, thanks for a awesome software :)