Fix issue #103

[hallazzang]

I think the problem is related to OS.
In my Windows machine, the directory <projectpath>/.chalice/venv structure looks like this:

venv/
    include/
        ...
    Lib/
        ...
        site-packages/
            ...
        ...
    Scripts/
        ...
        pip.exe
        ...
    tcl/
        ...
    pip-selfcheck.json

I modified some codes to correct the paths.

[jamesls]

Thanks for the pull request. I think this will also fix #31 right?

[hallazzang]

Yes, I think so :)