Changing installer from http to https. Fixes the following issue:

#> git --version
git version 1.8.1.1
#> git clone http://github.com/nvie/gitflow.git
Cloning into 'gitflow'...
error: RPC failed; result=22, HTTP code = 400
fatal: The remote end hung up unexpectedly

Motivation: "GitHub recently started redirecting http repository access to https"
[Source: http://stackoverflow.com/questions/19006770/git-rpc-failed-result-22-http-code-400]