Apart from "-t" not being supported by zsh's `type`, it does not appear to work with bash, too. Fixes: http://github.com/defunkt/hub/issues/#issue/47
The completion for git 1.7.2 parses the output of `git help --all` to generate a list of available commands. The output from `hub help` does not conform to the same format or respect the `--all` flag. To fix this issue, we only display hub's extended help when the `--all` (or `-a`) flag is not present, falling back to git.