find_git raises KeyError on 32 bt windows

[carlost]

find_git in git.py uses os.environ to get environment values for "ProgramFiles" and "ProgramFiles(x86)". Unfortunately, 32-bit windows doesn't have a key set for "ProgramFiles(x86)". The dictionary returned by os.environ will raise a KeyError because a key of "ProgramFiles(x86)" is not present.

if os.name == 'nt':
    extra_paths = (
        os.path.join(os.environ["ProgramFiles"], "Git", "bin"),
        os.path.join(os.environ["ProgramFiles(x86)"], "Git", "bin"),
    )

My python is pretty rank but you may want to replace this with a call to os.environ.get or os.getenv. Those seem to be far more forgiving ...