ui: fix deleting datastore without 'keep-job-configs'

without any default value in the viewModel, the resulting url would be:

`<id>?destroy-data=<value>&keep-job-configs=`

which is missing the actual value, so add the default

Fixes: e9979a1a ("ui: add 'keep configs' checkbox to datastore removal window")
Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
Tested-by: Fiona Ebner <f.ebner@proxmox.com>

www/datastore/OptionView.js

@@ -10,6 +10,7 @@ Ext.define('PBS.window.SafeDatastoreDestroy', {
     viewModel: {
 	data: {
 	    'destroyData': 0,
+	    'keepJobConfigs': 0,
 	},
 	formulas: {
 	    destroyNote: get => get('destroyData')