Improvised the 'transform/options' function usage with the Select2Cell.

The current implementaton binds the cell/control object, and the ajax
data in the asychronous Cells/Controls with the 'options' functions
extended from the Select2Cell.

The problem starts when we try to fetch the current model from that
options/transform/filter function to do some operation, which does not
require in most of the cases. Except the privileges control - where we
needed the current model for omitting the existing selected object
during transformation, and filtering.

In order resolved the issue, we need a common object, which is shared
among the Cell. In backgrid, the 'Column' object is mong the cell,
hence - implementation logic has been changed to bid the 'Column' object
with the 'options' function and, passed the 'Cell' object as an
arguments.

Because - we do use the common function 'transform' between 'Control'
and 'Cell', we needed make changes in the Select2Control to pass the
Control object as an arguments.

And, make the changes in the privileges control to use the new
implementation. The same logic is also required in some of the
operations, we will be/are working on the table/column nodes.

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

@@ -153,8 +153,7 @@ function($, _, pgAdmin, Backbone, Backform, Alertify, Node) {
        * and schema has disabled property then we need to apply it
        */
       if(!_.has(select2_opts, 'disabled') && (d && d.disabled)) {
-        _.extend(select2_opts, {
-          disabled: evalF(d.disabled, d, this.model)
+        _.extend(select2_opts, {disabled: evalF(d.disabled, d, this.model)
         });
       }
 
@@ -178,9 +177,11 @@ function($, _, pgAdmin, Backbone, Backform, Alertify, Node) {
     if(!optimage){
       return opt.text;
     } else {
-      return $(
-          '<span><span class="wcTabIcon ' + optimage + '"/>' + opt.text + '</span>'
-          );
+      return $('<span></span>').append(
+        $('<span></span>', {class: "wcTabIcon " + optimage})
+      ).append(
+        $('<span></span>').text(opt.text)
+      );
     }
   };
 
@@ -383,7 +384,7 @@ function($, _, pgAdmin, Backbone, Backform, Alertify, Node) {
           // We will transform the data later, when rendering.
           // It will allow us to generate different data based on the
           // dependencies.
-          column.set('options', transform.bind(self, data));
+          column.set('options', transform.bind(column, data));
         } else {
           column.set('options', data);
         }
@@ -401,7 +402,7 @@ function($, _, pgAdmin, Backbone, Backform, Alertify, Node) {
           editable = Backgrid.callByNeed(col.editable, column, model),
           optionValues = _.clone(this.optionValues ||
                 _.isFunction(this.column.get('options')) ?
-                    this.column.get('options').apply(this) :
+                    (this.column.get('options'))(this) :
                     this.column.get('options')),
           select2_opts = _.defaults({}, col.select2, this.defaults.select2),
           evalF = function(f, col, m) {
@@ -443,13 +444,12 @@ function($, _, pgAdmin, Backbone, Backform, Alertify, Node) {
               (_.indexOf(selectedValues, optionValue) > -1)
           }));
       }
+
       // Initialize select2 control.
       this.$select.select2(
-          _.defaults(
-            {'disabled': !editable},
-            col.select2,
-            this.defaults.select2
-            ));
+        _.defaults(
+          {'disabled': !editable}, col.select2, this.defaults.select2
+        ));
 
       /*
        * If select2 options do not have any disabled property on this cell
@@ -460,7 +460,6 @@ function($, _, pgAdmin, Backbone, Backform, Alertify, Node) {
           disabled: evalF(col.disabled, col, this.model)
         });
       }
-
       this.$el.find("select").select2(select2_opts);
 
       this.delegateEvents();
@@ -474,8 +473,8 @@ function($, _, pgAdmin, Backbone, Backform, Alertify, Node) {
     defaults: _.extend({}, NodeAjaxOptionsCell.prototype.defaults, {
       url: 'nodes',
       filter: undefined,
-      transform: function(rows) {
-        var self = this,
+      transform: function(rows, control) {
+        var self = control || this,
             node = self.column.get('schema_node'),
             res = [],
             filter = self.column.get('filter') || function() { return true; };
@@ -518,8 +517,8 @@ function($, _, pgAdmin, Backbone, Backform, Alertify, Node) {
     defaults: _.extend({}, NodeAjaxOptionsCell.prototype.defaults, {
       url: 'nodes',
       filter: undefined,
-      transform: function(rows) {
-        var self = this,
+      transform: function(rows, control) {
+        var self = control || this,
             node = self.column.get('schema_node'),
             res = [],
             filter = self.column.get('filter') || function() { return true; };