Use a python script to define Pylint config rather than an ini file (#69)

diff --git a/tox.ini b/tox.ini
index 1ef803c..f41ffd1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -73,8 +73,7 @@
     --import-order-style=google \
     --application-import-names="google,tests,system_tests" \
     google tests
-  pylint --rcfile pylintrc google
-  pylint --rcfile pylintrc.tests tests system_tests
+  python {toxinidir}/scripts/run_pylint.py
 deps =
   flake8
   flake8-import-order