webadmin: Add validation to new template

In PR [1], the validation of a new template was
removed from the UI in assumption that the backend
can validate the template properly. However,
the backend does not contain validation for the name
and if the name is not provided, it fails on inserting
null to a not null database column.

This patch adds the name validation back to the fronted.

1: oVirt#621

frontend/webadmin/modules/uicommonweb/src/main/java/org/ovirt/engine/ui/uicommonweb/models/vms/UnitVmModel.java

@@ -3250,7 +3250,7 @@ public void fireValidationCompleteEvent() {
         ValidationCompleteEvent.fire(getEventBus(), this);
     }
 
-    private boolean validateNaming() {
+    public boolean validateNaming() {
         getName().validateEntity(
                 new IValidation[] {
                         new NotEmptyValidation(),

frontend/webadmin/modules/uicommonweb/src/main/java/org/ovirt/engine/ui/uicommonweb/models/vms/VmListModel.java

@@ -1303,6 +1303,10 @@ private void onNewTemplate() {
             return;
         }
 
+        if (!model.validateNaming()) {
+            return;
+        }
+
         if (model.getIsSubTemplate().getEntity()) {
             postNameUniqueCheck();
         } else {