Prevent error message on git flow version

[leonardinius]

Seems the same problem as #235

The error was "line 113: init: command not found"

My gut feeling is what git flow version command does not require to invoke flow-initialization logics.

[petervanderdoes]

This is implemented in my fork git-flow (AVH Edition)
My fork has diverged to much to make this into an easy pull request for nvie's gitflow,

Checkout the changelog for more information about bugfixes and new features implemented in my fork.

[leonardinius]

Close to "archive" old issue.