Demo page throws error when deleting feature

[tomsaleeba]

Steps:

• open the index.html demo page
• draw a feature
• delete the feature
• check the JS console

Expected:
The feature is deleted and no errors are shown in the console.

Actual:
The feature is deleted but the following error is shown in the console

angular.js:12477 ReferenceError: layer is not defined
    at Object.deleted ((index):77)
    at (index):95
    at n.$emit (angular.js:16238)
    at ui-leaflet.js:4951
    at n.$eval (angular.js:15989)
    at n.$digest (angular.js:15800)
    at angular.js:16028
    at e (angular.js:5507)
    at angular.js:5784

The problem is the drawnItems.removeLayer(layer); line. I've found that making the whole deleted handler function a NOOP one like most of the others fixes the problem. The feature is deleted and no errors are thrown. I'll submit a pull request.