Path prefix not added to "move" operation in JSON patch

[rmorshea]

We send changes over in the form:

{
    "path": "/prefix",
    "changes": [{"op": "move", "path": "/x", "from": "/y"}]
}

On the client-side this should be reconstructed into the patch:

[{"op": "move", "path": "/prefix/x", "from": "/prefix/y"}]

However we are only adding the /prefix to the path key:

[{"op": "move", "path": "/prefix/x", "from": "/y"}]