Remove get_series unit test -- as get_series doesnt exist anymore

Author: cderici

tests/unit/test_model.py

@@ -104,25 +104,6 @@ def test_apply_delta(self):
         self.assertTrue(prev)
 
 
-@pytest.mark.asyncio
-def test_get_series():
-    from juju.model import Model
-    model = Model()
-    entity = {
-        'Meta': {
-            'supported-series': {
-                'SupportedSeries': [
-                    'xenial',
-                    'trusty',
-                ],
-            },
-        },
-    }
-    assert model._get_series('xenial/ubuntu', entity) == 'xenial'
-    assert model._get_series('ubuntu', entity) == 'xenial'
-    assert model._get_series('ch:ubuntu', entity) == 'xenial'
-
-
 class TestContextManager(asynctest.TestCase):
     @asynctest.patch('juju.model.Model.disconnect')
     @asynctest.patch('juju.model.Model.connect')