Try with the fixed release of astroid

pylint/__pkginfo__.py

@@ -22,7 +22,7 @@ numversion = (1, 7, 0)
 version = '.'.join([str(num) for num in numversion])
 install_requires = [
-    'astroid>=1.5.0',
+    'astroid>=1.5.1',
     'six',
     'isort >= 4.2.5',
     'mccabe',

tox.ini

@@ -4,14 +4,14 @@ skip_missing_interpreters = true
 [testenv:pylint]
 deps =
-   astroid>=1.5.0
+   astroid>=1.5.1
    isort
 commands = pylint -rn --rcfile={toxinidir}/pylintrc --load-plugins=pylint.extensions.docparams, pylint.extensions.mccabe {envsitepackagesdir}/pylint
 [testenv]
 deps =
-   astroid>=1.5.0
+   astroid>=1.5.1
    coverage
    isort
    mccabe