Redirect the focus of original input to Select2

Redirect the focus of original input to the "focus" event of Select2.
this way, we get back the accessible label for feature of previous Select2 versions.

select2.js

@@ -2096,6 +2096,7 @@ the specific language governing permissions and limitations under the Apache Lic
             this.focusser.attr("id", "s2id_autogen"+idSuffix);
 
             elementLabel = $("label[for='" + this.opts.element.attr("id") + "']");
+            this.opts.element.focus(this.bind(function () { this.focus(); }));
 
             this.focusser.prev()
                 .text(elementLabel.text())
@@ -2686,6 +2687,7 @@ the specific language governing permissions and limitations under the Apache Lic
             this.search.prev()
                 .text($("label[for='" + this.opts.element.attr("id") + "']").text())
                 .attr('for', this.search.attr('id'));
+            this.opts.element.focus(this.bind(function () { this.focus(); }));
 
             this.search.on("input paste", this.bind(function() {
                 if (this.search.attr('placeholder') && this.search.val().length == 0) return;