Adds API documentation for update snapshot status

Adds v2 and v3 API documentation for snapshot, actions API calls.

Change-Id: I7d6d511d353d5a2acd3c2c31356c28e8ae589604
Closes-Bug: #1532645

api-ref/source/v2/samples/snapshot-status-reset-request.json

@@ -0,0 +1,5 @@
+{
+    "os-reset_status": {
+        "status": "available",
+    }
+}

api-ref/source/v2/volumes-v2-snapshots-actions.inc

@@ -0,0 +1,34 @@
+.. -*- rst -*-
+
+====================================
+Snapshot actions (snapshots, action)
+====================================
+
+Administrator only. Resets status for a snapshot.
+
+
+Reset a snapshot's status
+=========================
+
+.. rest_method::  POST /v2/{tenant_id}/snapshots/{snapshot_id}/action
+
+Resets the status. Specify the ``os-reset_status`` action in the request body.
+
+Normal response codes: 202,
+
+
+Request
+-------
+
+.. rest_parameters:: parameters.yaml
+
+   - status: status_2
+   - os-reset_status: os-reset_status
+   - tenant_id: tenant_id
+   - snapshot_id: snapshot_id
+
+Request Example
+---------------
+
+.. literalinclude:: ./samples/snapshot-status-reset-request.json
+   :language: javascript

api-ref/source/v3/samples/snapshot-status-reset-request.json

@@ -0,0 +1,5 @@
+{
+    "os-reset_status": {
+        "status": "available",
+    }
+}

api-ref/source/v3/volumes-v3-snapshots-actions.inc

@@ -0,0 +1,34 @@
+.. -*- rst -*-
+
+====================================
+Snapshot actions (snapshots, action)
+====================================
+
+Administrator only. Resets status for a snapshot.
+
+
+Reset a snapshot's status
+=========================
+
+.. rest_method::  POST /v3/{tenant_id}/snapshots/{snapshot_id}/action
+
+Resets the status. Specify the ``os-reset_status`` action in the request body.
+
+Normal response codes: 202,
+
+
+Request
+-------
+
+.. rest_parameters:: parameters.yaml
+
+   - status: status_2
+   - os-reset_status: os-reset_status
+   - tenant_id: tenant_id
+   - snapshot_id: snapshot_id
+
+Request Example
+---------------
+
+.. literalinclude:: ./samples/snapshot-status-reset-request.json
+   :language: javascript