Dialog: Fix typo

Closes jquerygh-1447

Thanks Spencer Davis
(cherry picked from commit d95c23a)

Author: scottgonzalez

ui/dialog.js

@@ -229,10 +229,10 @@ return $.widget( "ui.dialog", {
 
 	_moveToTop: function( event, silent ) {
 		var moved = false,
-			zIndicies = this.uiDialog.siblings( ".ui-front:visible" ).map(function() {
+			zIndices = this.uiDialog.siblings( ".ui-front:visible" ).map(function() {
 				return +$( this ).css( "z-index" );
 			}).get(),
-			zIndexMax = Math.max.apply( null, zIndicies );
+			zIndexMax = Math.max.apply( null, zIndices );
 
 		if ( zIndexMax >= +this.uiDialog.css( "z-index" ) ) {
 			this.uiDialog.css( "z-index", zIndexMax + 1 );