api-ref: Fix response code and parameters in evacuate

* Unnecessary note is removed.

* The 'on_shared_storage' parameter
  The max version is 2.13.
  Improve the description.

* The 'evacuate' parameter
  Fix the type and the description.

* The 'adminPass' parameter
  Fix the description and remove max version.

* The 'host' parameter
  Improve the description.

* response code
  Remove unncessary response codes.
  Add a missing response code.

Change-Id: Ic857333ac25bee26e3ec22106b1b8fda2389b967
Implements: blueprint api-ref-in-rst-pike
Closes-Bug: #1683264

api-ref/source/parameters.yaml

@@ -1083,12 +1083,13 @@ adminPass_evacuate:
   max_version: 2.13
 adminPass_evacuate_request:
   description: |
-    An administrative password to access the evacuated instance. If you omit this parameter, the operation
-    generates a new password.
+    An administrative password to access the evacuated server.
+    If you omit this parameter, the operation generates a new password.
+    Up to API version 2.13, if ``onSharedStorage`` is set to ``True`` and
+    this parameter is specified, an error is raised.
   in: body
   required: false
   type: string
-  max_version: 2.13
 adminPass_request:
   description: |
     The administrative password of the server. If you omit this parameter, the operation
@@ -1853,10 +1854,10 @@ errors:
   type: integer
 evacuate:
   description: |
-    Specify the ``evacuate`` action in the request body.
+    The action to evacuate a server to another host.
   in: body
   required: true
-  type: string
+  type: object
 event:
   description: |
     The name of the event.
@@ -2383,6 +2384,7 @@ guest_format:
 host:
   description: |
     The name or ID of the host to which the server is evacuated.
+    If you omit this parameter, the scheduler chooses a host.
   in: body
   required: false
   type: string
@@ -3500,10 +3502,16 @@ new_file:
 on_shared_storage:
   description: |
     Server on shared storage.
+
+    .. note::
+
+      Starting since version 2.14, Nova automatically detects
+      whether the server is on shared storage or not.
+      Therefore this parameter was removed.
   in: body
   required: true
   type: boolean
-  max_version: 2.14
+  max_version: 2.13
 os:
   description: |
     The name of the operating system.

api-ref/source/servers-action-evacuate.inc

@@ -1,4 +1,3 @@
-.. note:: Microversion 2.23 or greater is required for this API.
 .. -*- rst -*-
 
 Evacuate Server (evacuate Action)
@@ -14,8 +13,8 @@ Evacuates a server from a failed host to a new host.
 
 Normal response codes: 200
 
-Error response codes: computeFault(400, 500), serviceUnavailable(503), badRequest(400),
-unauthorized(401), forbidden(403), badMethod(405), itemNotFound(404)
+Error response codes: badRequest(400), unauthorized(401), forbidden(403),
+itemNotFound(404), conflict(409)
 
 Request
 -------