ui: namespace selector: show picker empty text if no namespace

by filtering out the empty namespace from the api, and putting
manually a div with the grid-empty xclass around the gettext

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
 [ T: reword commit message ]
Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

www/form/NamespaceSelector.js

@@ -34,8 +34,8 @@ Ext.define('PBS.form.NamespaceSelector', {
 	minWidth: 170,
 	maxWidth: 500,
 	// below doesn't work :/
-	//minHeight: 30,
-	//emptyText: gettext('No namespaces accesible.'),
+	minHeight: 30,
+	emptyText: `<div class="x-grid-empty">${gettext('No namespaces accessible.')}</div>`,
     },
 
     triggers: {
@@ -82,6 +82,7 @@ Ext.define('PBS.form.NamespaceSelector', {
 	me.store = Ext.create('Ext.data.Store', {
 	    model: 'pbs-namespaces',
 	    autoLoad: !!me.datastore,
+	    filters: (rec) => rec.data.ns !== '',
 	    proxy: {
 		type: 'proxmox',
 		timeout: 30 * 1000,