api-ref: mark name as optional in volume create API

The "name" parameter to the volume create API is optional,
this makes the docs reflect that. While in here, I've
renamed volume_name_1 to volume_name_optional so the variable
name is descriptive and dropped the redundant name_8 variable.

Change-Id: Ice42f06112a268b229f770f34096de19eb3447b2
Closes-Bug: #1794115

api-ref/source/v2/parameters.yaml

@@ -1122,12 +1122,6 @@ name_7:
   in: body
   required: true
   type: string
-name_8:
-  description: |
-    The volume name.
-  in: body
-  required: false
-  type: string
 name_9:
   description: |
     The consistency group name.
@@ -1743,6 +1737,12 @@ volume_name:
   in: body
   required: true
   type: string
+volume_name_optional:
+  description: |
+    The volume name.
+  in: body
+  required: false
+  type: string
 volume_type_1:
   description: |
     A ``volume_type`` object.

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

@@ -185,7 +185,7 @@ Request
    - multiattach: multiattach_req
    - availability_zone: availability_zone
    - source_volid: source_volid
-   - name: name_13
+   - name: volume_name_optional
    - volume: volume
    - consistencygroup_id: consistencygroup_id_1
    - volume_type: volume_type_2

api-ref/source/v3/ext-backups.inc

@@ -233,7 +233,7 @@ Request
    - project_id: project_id_path
    - backup_id: backup_id
    - restore: restore
-   - name: name_8
+   - name: volume_name_optional
    - volume_id: volume_id_6
 
 Request Example

api-ref/source/v3/parameters.yaml

@@ -1884,12 +1884,6 @@ name_6:
   in: body
   required: false
   type: string
-name_8:
-  description: |
-    The volume name.
-  in: body
-  required: false
-  type: string
 name_9:
   description: |
     The consistency group name.
@@ -2967,7 +2961,7 @@ volume_name:
   in: body
   required: true
   type: string
-volume_name_1:
+volume_name_optional:
   description: |
     The volume name.
   in: body

api-ref/source/v3/volume-manage.inc

@@ -47,7 +47,7 @@ Request
    - availability_zone: availability_zone
    - bootable: bootable_1
    - volume_type: volume_type
-   - name: volume_name_1
+   - name: volume_name_optional
    - host: host_mutex
    - cluster: cluster_mutex
    - ref: ref

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

@@ -199,7 +199,7 @@ Request
    - multiattach: multiattach_req
    - snapshot_id: snapshot_id
    - backup_id: backup_id_1
-   - name: name_13
+   - name: volume_name_optional
    - imageRef: imageRef
    - volume_type: volume_type_2
    - metadata: metadata_10
@@ -404,7 +404,7 @@ Request
    - volume_id: volume_id_path
    - volume: volume
    - description: description_5
-   - name: name_8
+   - name: volume_name_optional
    - metadata: metadata_2
 
 Request Example