pylint_plugin: Support pylint 2 / astroid 2
pylint_plugin: Support pylint 2 / astroid 2

Tested with pylint 2.4.4 / astroid 2.3.3 (the latest versions on PyPI
today).

stb-tester/stb-tester,stb-tester/stb-tester,stb-tester/stb-tester,stb-tester/stb-tester