RESOLVIDO:
Encontrei a solução aqui: link e funciona bem.
I got that by using curl from the URL here:
curl https://raw.github.com/git/git/master/contrib/completion/git-completion.bash -o ~/.git-completion.bash
Then I added to my
~/.bash_profile
file the following "execute if it exists" code:
if [ -f ~/.git-completion.bash ]; then . ~/.git-completion.bash; fi