unexpected-keyword-arg false positive for subprocess.Popen in Python 3.6

[eight04]

Steps to reproduce

When linting following snippet

from subprocess import Popen, PIPE

Popen("foo", stdin=PIPE, stdout=PIPE, encoding="utf-8")

Current behavior

No config file found, using default configuration
************* Module test
C:  1, 0: Missing module docstring (missing-docstring)
C:  3, 0: Invalid constant name "p" (invalid-name)
E:  3, 4: Unexpected keyword argument 'encoding' in constructor call (unexpected
-keyword-arg)

----------------------------------------------------------------------
Your code has been rated at -25.00/10 (previous run: -25.00/10, +0.00)

Expected behavior

encoding and errors are new in python 3.6 and shouldn't raise unexpected-keyword-arg.

I think there are other functions under subprocess also affect by this.

pylint --version output

No config file found, using default configuration
pylint 1.7.0,
astroid 1.5.0
Python 3.6.0 (v3.6.0:41df79263a11, Dec 23 2016, 07:18:10) [MSC v.1900 32 bit (In
tel)]

[rogalski]

Thank you for submitting a bug!

Root cause is an incomplete definition in astroid.brain module.

Pull requests are welcome!