Run pylint on tests

Drop support for pylint < 1.0

Enable ignoring unknown attributes on modules (both nose and pytest
use advanced techniques, support for which only made it to pylint
recently)

Fix some bugs revealed by pylint

Do minor refactoring or add pylint:disable directives where the
linter complains.

Reviewed-By: Tomas Babej <tbabej@redhat.com>

ipatests/util.py

@@ -430,7 +430,7 @@ class ClassChecker(object):
 
     def __get_cls(self):
         if self.__cls is None:
-            self.__cls = self._cls
+            self.__cls = self._cls  # pylint: disable=E1101
         assert inspect.isclass(self.__cls)
         return self.__cls
     cls = property(__get_cls)
@@ -455,19 +455,6 @@ class ClassChecker(object):
         context.__dict__.clear()
 
 
-def check_TypeError(value, type_, name, callback, *args, **kw):
-    """
-    Tests a standard TypeError raised with `errors.raise_TypeError`.
-    """
-    e = raises(TypeError, callback, *args, **kw)
-    assert e.value is value
-    assert e.type is type_
-    assert e.name == name
-    assert type(e.name) is str
-    assert str(e) == ipalib.errors.TYPE_ERROR % (name, type_, value)
-    return e
-
-
 def get_api(**kw):
     """
     Returns (api, home) tuple.
@@ -503,7 +490,7 @@ class PluginTester(object):
 
     def __get_plugin(self):
         if self.__plugin is None:
-            self.__plugin = self._plugin
+            self.__plugin = self._plugin  # pylint: disable=E1101
         assert issubclass(self.__plugin, Plugin)
         return self.__plugin
     plugin = property(__get_plugin)