Pin Pylint and Astroid versions to avoid bugs

pylint-dev/pylint-django#108

Author: jambonrose

requirements.txt

@@ -1,3 +1,4 @@
+astroid==1.5.3
 bumpversion==0.5.3
 check-manifest==0.36
 coverage==4.4.2
@@ -9,7 +10,7 @@ flake8-quotes==0.13.0
 flake8==3.5.0
 Pygments==2.2.0
 pylint-django==0.7.2
-pylint==1.8.1
+pylint==1.7.5
 python-dateutil==2.6.1
 setuptools==38.4.0
 tox==2.9.1