Use environment variables provided as an argument to run()

Previously, they were accidentally being discarded during the encoding
step.

Resolves sarugaku#55

src/vistir/misc.py

@@ -286,14 +286,11 @@ def run(
  _env = os.environ.copy()
  if env:
  _env.update(env)
- env = _env
  if six.PY2:
  fs_encode = partial(to_bytes, encoding=locale_encoding)
- _env = {fs_encode(k): fs_encode(v) for k, v in os.environ.items()}
- for key, val in env.items():
- _env[fs_encode(key)] = fs_encode(val)
+ _env = {fs_encode(k): fs_encode(v) for k, v in _env.items()}
  else:
- _env = {k: fs_str(v) for k, v in os.environ.items()}
+ _env = {k: fs_str(v) for k, v in _env.items()}
  if not spinner_name:
  spinner_name = "bouncingBar"
  if six.PY2: