Selectmenu: Remove broken tabindex code

(cherry picked from commit 1fb0879)

Author: scottgonzalez

ui/selectmenu.js

@@ -67,8 +67,7 @@ return $.widget( "ui.selectmenu", {
 	},
 
 	_drawButton: function() {
-		var that = this,
-			tabindex = this.element.attr( "tabindex" );
+		var that = this;
 
 		// Associate existing label with the new button
 		this.label = $( "label[for='" + this.ids.element + "']" ).attr( "for", this.ids.button );
@@ -85,7 +84,7 @@ return $.widget( "ui.selectmenu", {
 		// Create button
 		this.button = $( "<span>", {
 			"class": "ui-selectmenu-button ui-widget ui-state-default ui-corner-all",
-			tabindex: tabindex || this.options.disabled ? -1 : 0,
+			tabindex: this.options.disabled ? -1 : 0,
 			id: this.ids.button,
 			role: "combobox",
 			"aria-expanded": "false",