Description of problem:
When adding an embedded (add-on) cartridge, I get a response wheren the "url" property is always undefined

Version-Release number of selected component (if applicable):
protocol 1.2

How reproducible:
add an add-on cartridge, inspect the json you get back, look for the "url"-property

Steps to Reproduce:
1. add an add-on cartridge
2. inspect the json you get back
3. inspect the "url" property

Actual results:
the "url" property is "undefined", the info is present in the "connection_url" property though:

<snip>
{
    ...
    "name" => "mongodb-2.2",
    "properties" => [
        ...
        {
            "name" => "connection_url",
            "type" => "cart_data",
            "description" => "Mongo DB connection URL",
            "value" => "mongodb://$OPENSHIFT_MONGODB_DB_HOST:$OPENSHIFT_MONGODB_DB_PORT/"
        }
    ],
    ...
    "type" => "embedded",
    "url" => undefined,
    ...
}
</snip>

Expected results:
the "url" property should match the value of the "connection_url" property

Additional info: