ansible: 1.2.2 some fixes

-   Install the Python module `ansible` into the usual prefix, but use
    `python.private_site_packages` (in `libexec`) for the deps.
-   In oder for the `ansible` module to be useful, the deps are needed
    and we insert the `python.private_site_packages` in the
    `ansible/__init__.py` as a `sitedir`, to the `egg`s are working.
-   Rewrote the `bin_wrapper` to be ready to be moved into
    `python_helper` or something.
-   With the brand new changes in the PythonInstalled dependency,
    it is not necessary to set the `PYTHONPATH` if you want to use
    the `python.private_site_packages` inside of the `libexec`.
    However, you have to put the calls to `system python` inside of
    a `python do … end` block (technical limitation of supporting
    Python 2.x and 3.x in general).