Change the way to get the name of the current shell

[terut]

The current way to get the name of the using shell doesn't work in some situations.

My default shell is bash, but I use zsh on tmux and then ndenv-init loads completions/ndenv.bash in zsh on tmux.

Now, rbenv use the different way to get the shell's name. https://github.com/sstephenson/rbenv/blob/master/libexec/rbenv-init#L23

[riywo]

Hi @terut ,

Thanks!

[terut]

You, too. :smile: