Drop pylint for the time being. It served us well (#231)

Author: Jon Wayne Parrott

packages/google-auth/.travis.yml

@@ -2,7 +2,7 @@ language: python
 sudo: false
 matrix:
   include:
-  - python: 3.5
+  - python: 3.6
     env: TOXENV=lint
   - python: 3.6
     env: TOXENV=docs

packages/google-auth/pylint.config.py

@@ -70,20 +70,14 @@ deps =
 commands = make -C docs html
 
 [testenv:lint]
-basepython = python3.5
+basepython = python3.6
 commands =
-  python setup.py check --metadata --restructuredtext --strict
   flake8 \
     --import-order-style=google \
     --application-import-names="google,tests,system_tests" \
     google tests
-  gcp-devrel-py-tools run-pylint \
-    --config pylint.config.py \
-    --library-filesets google \
-    --test-filesets tests system_tests
+  python setup.py check --metadata --restructuredtext --strict
 deps =
   flake8
   flake8-import-order
-  pylint
   docutils
-  gcp-devrel-py-tools