Resolve overcloud key file path relative to tobiko.conf file

Change-Id: I36fd159b0e1c3c7f3fdf01880549410291edc175

tobiko/tests/functional/tripleo/test_overcloud.py

@@ -78,7 +78,7 @@ class OvercloudNovaApiTest(testtools.TestCase):
                          host_config.port)
         self.assertEqual(CONF.tobiko.tripleo.overcloud_ssh_username,
                          host_config.username)
-        key_filename = os.path.expanduser(
+        key_filename = tobiko.tobiko_config_path(
             CONF.tobiko.tripleo.overcloud_ssh_key_filename)
         self.assertEqual(key_filename, host_config.key_filename)
         self.assertTrue(os.path.isfile(key_filename))

tobiko/tripleo/overcloud.py

@@ -89,7 +89,7 @@ class OvercloudSshKeyFileFixture(tobiko.SharedFixture):
 
     @property
     def key_filename(self):
-        return os.path.expanduser(
+        return tobiko.tobiko_config_path(
             CONF.tobiko.tripleo.overcloud_ssh_key_filename)
 
     def setup_fixture(self):