Fix installation of pylint from source with no locale

[asottile]

Originally reported here

before

$ LANG= pip install .
Processing /tmp/pylint
    ERROR: Command errored out with exit status 1:
     command: /tmp/pylint/venv/bin/python -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-req-build-lfux_z14/setup.py'"'"'; __file__='"'"'/tmp/pip-req-build-lfux_z14/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /tmp/pip-req-build-lfux_z14/pip-egg-info
         cwd: /tmp/pip-req-build-lfux_z14/
    Complete output (7 lines):
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/tmp/pip-req-build-lfux_z14/setup.py", line 60, in <module>
        long_description = stream.read()
      File "/usr/lib/python3.6/encodings/ascii.py", line 26, in decode
        return codecs.ascii_decode(input, self.errors)[0]
    UnicodeDecodeError: 'ascii' codec can't decode byte 0xc2 in position 4020: ordinal not in range(128)
    ----------------------------------------
ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.

after

$ LANG= pip install .
Processing /tmp/pylint

...

Building wheels for collected packages: pylint
  Building wheel for pylint (setup.py) ... done
  Created wheel for pylint: filename=pylint-2.5.0.dev1-py3-none-any.whl size=314883 sha256=7fe1d61f7b58128a873402c6e34569c6955c308ffa39573d9f04b71e787ff91d
  Stored in directory: /tmp/pip-ephem-wheel-cache-gzhtmun_/wheels/3f/a4/93/7ac93f1ad87ac0786cc139aa1f0f4e59daf837168f91f028b3
Successfully built pylint
Installing collected packages: six, lazy-object-proxy, typed-ast, wrapt, astroid, isort, mccabe, toml, pylint
Successfully installed astroid-2.3.3 isort-4.3.21 lazy-object-proxy-1.4.3 mccabe-0.6.1 pylint-2.5.0.dev1 six-1.14.0 toml-0.10.0 typed-ast-1.4.1 wrapt-1.11.2

[PCManticore]

Thank you for the cleanup, much appreciated!