v3 docs: Remove accidentally duplicated section

We ended up with two "Errors" sections in the upgrade guide after the
recent refactor. Removing one of them.

Authored-by: Reid Mitchell <rmitchell@pivotal.io>

Author: reidmit

docs/v3/source/includes/upgrade_guide/conceptual_changes/_asynchronous_operations.md

@@ -7,65 +7,3 @@ For clients that want to report the outcome of an asynchronous operation, the ex
 An example of an asynchronous endpoint is the [delete app endpoint](#delete-an-app).
 
 Read more about [the job resource](#jobs).
-
-<!-- We need to use plain html here to specify different ids. Otherwise the framework will mess up urls -->
-<h3 id="errors-v3">Errors</h3>
-
-```
-Example Request
-```
-
-```shell
-curl "https://api.example.org/v2/apps/not-found" \
-  -X GET \
-  -H "Authorization: bearer [token]"
-```
-
-```
-Example Response
-```
-
-```http
-HTTP/1.1 404 Not Found
-Content-Type: application/json
-
-{
-   "description": "The app could not be found: not-found",
-   "error_code": "CF-AppNotFound",
-   "code": 100004
-}
-```
-
-```
-Example Request
-```
-
-```shell
-curl "https://api.example.org/v3/apps/not-found" \
-  -X GET \
-  -H "Authorization: bearer [token]"
-```
-
-```
-Example Response
-```
-
-```http
-HTTP/1.1 404 Not Found
-Content-Type: application/json
-
-{
-   "errors": [
-      {
-         "detail": "App not found",
-         "title": "CF-ResourceNotFound",
-         "code": 10010
-      }
-   ]
-}
-```
-
-The V3 API returns an array of errors instead of a single error like in V2.
-
-Clients may wish to display all returned errors.
-