Skip tests affected by bug 695

Skip test `CreateSuccessTestCase.test_location_header` in module
`pulp_smash.tests.platform.api_v2.test_repository` if Pulp 2.6 or older is
targeted.

Test suite results do not change when run against Pulp 2.7 (and the Pulp Smash
settings file is configured appropriately). This fixes two failing tests when
run against Pulp 2.6.

Test results before this change:

    $ PULP_SMASH_CONFIG_FILE=pulp-2.6.json python -m unittest2 \
    >   pulp_smash.tests.platform.api_v2.test_repository
    …
    Ran 11 tests in 1.947s

    FAILED (failures=8)

Test results with this change applied:

    $ PULP_SMASH_CONFIG_FILE=pulp-2.6.json python -m unittest2 \
    >   pulp_smash.tests.platform.api_v2.test_repository
    …
    Ran 11 tests in 1.961s

    FAILED (failures=6, skipped=1)

pulp_smash/tests/platform/api_v2/test_repository.py

@@ -20,7 +20,7 @@
 
 from pulp_smash.config import get_config
 from pulp_smash.constants import REPOSITORY_PATH, ERROR_KEYS
-from pulp_smash.utils import create_repository, delete, uuid4
+from pulp_smash.utils import create_repository, delete, require, uuid4
 from requests.exceptions import HTTPError
 from unittest2 import TestCase
 
@@ -54,6 +54,7 @@ def test_status_code(self):
             with self.subTest(self.bodies[i]):
                 self.assertEqual(response.status_code, 201)
 
+    @require('2.7')  # https://pulp.plan.io/issues/695
     def test_location_header(self):
         """Assert that the Location header is correctly set in the response."""
         for response, attrs in zip(self.responses, self.attrs_iter):