qmp-commands: move 'x-blockdev-change' doc to schema

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

docs/qmp-commands.txt

@@ -216,47 +216,3 @@ Return the QMP wire schema.  The returned value is a json-array of
 named schema entities.  Entities are commands, events and various
 types.  See docs/qapi-code-gen.txt for information on their structure
 and intended use.
-
-x-blockdev-change
------------------
-
-Dynamically reconfigure the block driver state graph. It can be used
-to add, remove, insert or replace a graph node. Currently only the
-Quorum driver implements this feature to add or remove its child. This
-is useful to fix a broken quorum child.
-
-If @node is specified, it will be inserted under @parent. @child
-may not be specified in this case. If both @parent and @child are
-specified but @node is not, @child will be detached from @parent.
-
-Arguments:
-- "parent": the id or name of the parent node (json-string)
-- "child": the name of a child under the given parent node (json-string, optional)
-- "node": the name of the node that will be added (json-string, optional)
-
-Note: this command is experimental, and not a stable API. It doesn't
-support all kinds of operations, all kinds of children, nor all block
-drivers.
-
-Warning: The data in a new quorum child MUST be consistent with that of
-the rest of the array.
-
-Example:
-
-Add a new node to a quorum
--> { "execute": "blockdev-add",
-     "arguments": { "driver": "raw",
-                    "node-name": "new_node",
-                    "file": { "driver": "file",
-                              "filename": "test.raw" } } }
-<- { "return": {} }
--> { "execute": "x-blockdev-change",
-     "arguments": { "parent": "disk1",
-                    "node": "new_node" } }
-<- { "return": {} }
-
-Delete a quorum's node
--> { "execute": "x-blockdev-change",
-     "arguments": { "parent": "disk1",
-                    "child": "children.1" } }
-<- { "return": {} }

qapi/block-core.json

@@ -3455,6 +3455,28 @@
 # the rest of the array.
 #
 # Since: 2.7
+#
+# Example:
+#
+# 1. Add a new node to a quorum
+# -> { "execute": "blockdev-add",
+#      "arguments": {
+#          "options": { "driver": "raw",
+#                       "node-name": "new_node",
+#                        "file": { "driver": "file",
+#                                  "filename": "test.raw" } } } }
+# <- { "return": {} }
+# -> { "execute": "x-blockdev-change",
+#      "arguments": { "parent": "disk1",
+#                     "node": "new_node" } }
+# <- { "return": {} }
+#
+# 2. Delete a quorum's node
+# -> { "execute": "x-blockdev-change",
+#      "arguments": { "parent": "disk1",
+#                     "child": "children.1" } }
+# <- { "return": {} }
+#
 ##
 { 'command': 'x-blockdev-change',
   'data' : { 'parent': 'str',