Fixes few UI issue with the backform controls.

1. NodeAjaxOtions needs to check 'version_compability' in field, and not
   'ver_in_limit' variable. (Thanks Murtuza for pointing that out.)
2. Override the input control to catch the change properly in it.
3. Updated the UniqueCollectionControl and Variable Control to render
   proper template in the header.

web/pgadmin/browser/static/js/node.ui.js

@@ -93,7 +93,7 @@ function($, _, pgAdmin, Backbone, Backform, Alertify, Node) {
          */
         var data = cache_node.cache(url, node_info, cache_level);
 
-        if (this.field.get('ver_in_limit') &&
+        if (this.field.get('version_compitible') &&
             (_.isUndefined(data) || _.isNull(data))) {
           m.trigger('pgadmin:view:fetching', m, self.field);
           $.ajax({