Use endpoint_override in version negotiation

Change [1] introduced the usage of endpoint_filter when deciding which
endpoint to use during version negotiation. This requires properly
setting interface/region/service_type in order to properly pick the
endpoint. But, sometimes (for example in Kolla-ansible), the endpoint
url is explicitly defined. In the event of the endpoint being explicitly
defined, it should take priority here.

It should be noted that even though SessionClient extends from
keystoneauth1's adapter.LegacyJsonAdapter, the `request` function within
_make_simple_request is being called on the nested Session object, not
the Adapter itself. If it was called on the Adapter this problem
wouldn't exist, as the `endpoint_override` (or `endpoint`) kwarg passed
in to the constructor of the SessionClient would already take
precedence.

Additionally: Adds a release note to the older branch as this is a
fix that needs to be released and is worthy of change visibility
in release notes.

[1]: I42b66daea1f4397273a3f4eb1638abafb3bb28ce

Change-Id: I69dc2c88648ba1d09a9ad3ab3435662e8d1ea6ff
Related-Bug: #1818295
(cherry picked from commit 8071d5d)
(cherry picked from commit b40630f)

ironicclient/common/http.py

@@ -620,7 +620,8 @@ def _make_simple_request(self, conn, method, url):
         # NOTE: conn is self.session for this class
         return conn.request(url, method, raise_exc=False,
                             user_agent=USER_AGENT,
-                            endpoint_filter=endpoint_filter)
+                            endpoint_filter=endpoint_filter,
+                            endpoint_override=self.endpoint_override)
 
     @with_retries
     def _http_request(self, url, method, **kwargs):

ironicclient/tests/unit/common/test_http.py

@@ -741,6 +741,7 @@ def test_make_simple_request(self):
                 'service_type': 'baremetal',
                 'region_name': ''
             },
+            endpoint_override='http://127.0.0.1',
             user_agent=http.USER_AGENT)
         self.assertEqual(res, session.request.return_value)
 

releasenotes/notes/fixes-endpoint-override-for-version-e6d25da654f0a7ff.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    Fixes an issue where an endpoint_override was not considered when
+    performing version negotiation, which would can result in the client
+    attempting to base version negotiation off of an entry in the service
+    catalog as opposed to an endpoint_override.