pylint: Update pylint to 1.7.1, run on tests/ and tools and fix complaints.

The motivation for this is that
 a.) 1.7.1 runs with python 3.6 (bionic)
 b.) we want to run pylint on tests/ and tools for the same reasons
     that we want to run it on cloudinit/

The changes are described below.
- Update tox.ini to invoke pylint v1.7.1.
- Modify .pylintrc generated-members ignore mocked object members (m_.*)
- Replace "dangerous" params defaulting to {}
- Fix up cloud_tests use of platforms
- Cast some instance objects to with dict()
- Handle python2.7 vs 3+ ConfigParser use of readfp (deprecated)
- Update use of assertEqual(<boolean>, value) to assert<Boolean>(value)
- replace depricated assertRegexp -> assertRegex
- Remove useless test-class calls to super class
- Assign class property accessors a result and use it
- Fix missing class member in CepkoResultTests
- Fix Cheetah test import

1 files changed, 6 insertions, 3 deletions

diff --git a/tests/unittests/test_datasource/test_digitalocean.py b/tests/unittests/test_datasource/test_digitalocean.py
index ec321733..3127014b 100644
--- a/tests/unittests/test_datasource/test_digitalocean.py
+++ b/tests/unittests/test_datasource/test_digitalocean.py
@@ -199,9 +199,8 @@ class TestDataSourceDigitalOcean(CiTestCase):
 
 class TestNetworkConvert(CiTestCase):
 
-    @mock.patch('cloudinit.net.get_interfaces_by_mac')
-    def _get_networking(self, m_get_by_mac):
-        m_get_by_mac.return_value = {
+    def _get_networking(self):
+        self.m_get_by_mac.return_value = {
             '04:01:57:d1:9e:01': 'ens1',
             '04:01:57:d1:9e:02': 'ens2',
             'b8:ae:ed:75:5f:9a': 'enp0s25',
@@ -211,6 +210,10 @@ class TestNetworkConvert(CiTestCase):
         self.assertIn('config', netcfg)
         return netcfg
 
+    def setUp(self):
+        super(TestNetworkConvert, self).setUp()
+        self.add_patch('cloudinit.net.get_interfaces_by_mac', 'm_get_by_mac')
+
     def test_networking_defined(self):
         netcfg = self._get_networking()
         self.assertIsNotNone(netcfg)