removing memchache mentions in comments

remove memcached folder as it is no longer needed, also address a couple grammatical errors

awx/conf/tests/unit/test_settings.py

@@ -66,15 +66,6 @@ def test_unregistered_setting(settings):
     assert settings.cache.get('DEBUG') is None
 
 
-def test_cached_settings_unicode_is_auto_decoded(settings):
-    # https://github.com/linsomniac/python-memcached/issues/79
-    # https://github.com/linsomniac/python-memcached/blob/288c159720eebcdf667727a859ef341f1e908308/memcache.py#L961
-
-    value = 'Iñtërnâtiônàlizætiøn'  # this simulates what python-memcached does on cache.set()
-    settings.cache.set('DEBUG', value)
-    assert settings.cache.get('DEBUG') == 'Iñtërnâtiônàlizætiøn'
-
-
 def test_read_only_setting(settings):
     settings.registry.register(
         'AWX_READ_ONLY',
@@ -254,31 +245,6 @@ def test_setting_from_db(settings, mocker):
         assert settings.cache.get('AWX_SOME_SETTING') == 'FROM_DB'
 
 
-@pytest.mark.parametrize('encrypted', (True, False))
-def test_setting_from_db_with_unicode(settings, mocker, encrypted):
-    settings.registry.register(
-        'AWX_SOME_SETTING',
-        field_class=fields.CharField,
-        category=_('System'),
-        category_slug='system',
-        default='DEFAULT',
-        encrypted=encrypted
-    )
-    # this simulates a bug in python-memcached; see https://github.com/linsomniac/python-memcached/issues/79
-    value = 'Iñtërnâtiônàlizætiøn'
-
-    setting_from_db = mocker.Mock(id=1, key='AWX_SOME_SETTING', value=value)
-    mocks = mocker.Mock(**{
-        'order_by.return_value': mocker.Mock(**{
-            '__iter__': lambda self: iter([setting_from_db]),
-            'first.return_value': setting_from_db
-        }),
-    })
-    with mocker.patch('awx.conf.models.Setting.objects.filter', return_value=mocks):
-        assert settings.AWX_SOME_SETTING == 'Iñtërnâtiônàlizætiøn'
-        assert settings.cache.get('AWX_SOME_SETTING') == 'Iñtërnâtiônàlizætiøn'
-
-
 @pytest.mark.defined_in_file(AWX_SOME_SETTING='DEFAULT')
 def test_read_only_setting_assignment(settings):
     "read-only settings cannot be overwritten"