Git external init command doesn't take into account the branch parameters.

[mskoczylas]

When you configure git external to a repo with a branch, the branch parameter is not taking into account when you init externals.
To fix:
On line 70 of git_external.rb
system "git clone #{url} #{path}"

This command should be there somewhere :D
system "git clone -b #{branch} #{url} #{path}"