Fix config var end point generations

Links on resources without properties like "config vars" in the Heroku
platform schema are currently being generated without parameters, even if
they specify that they have parameters in their `href`.

e.g.

``` ruby
 class ConfigVar
   def initialize(client)
     @client = client
   end

    # Get config-vars for app.
   def info()
     @client.config_var.info()
   end

    # Update config-vars for app. You can update existing config-vars by
setting them again, and remove by setting it to `NULL`.
   #
   # @param body: the object to pass as the request payload
   def update(body)
     @client.config_var.update(body)
   end
 end
```

This pull removes a check on the `properties` array so that these links can
be properly generated.

``` ruby
 class ConfigVar
   def initialize(client)
     @client = client
   end

    # Get config-vars for app.
   #
   # @param app_id_or_app_name: unique identifier of app or unique name of
app
   def info(app_id_or_app_name)
     @client.config_var.info(app_id_or_app_name)
   end

    # Update config-vars for app. You can update existing config-vars by
setting them again, and remove by setting it to `NULL`.
   #
   # @param app_id_or_app_name: unique identifier of app or unique name of
app
   # @param body: the object to pass as the request payload
   def update(app_id_or_app_name, body)
     @client.config_var.update(app_id_or_app_name, body)
   end
 end
```