fix ie9

Author: Narretz

src/ng/directive/ngOptions.js

@@ -472,10 +472,16 @@ var ngOptionsDirective = ['$compile', '$document', '$parse', function($compile,
 
           // Make sure to remove the selected attribute from the previously selected option
           // Otherwise, screen readers might get confused
-          if (selectedOption) selectedOption.element.removeAttribute('selected');
+          if (selectedOption) {
+            selectedOption.element.removeAttribute('selected');
+            selectedOption.element.selected = false; // IE9
+          }
 
           if (option) {
-            if (providedEmptyOption) emptyOption.removeAttr('selected');
+            if (providedEmptyOption) {
+              emptyOption.removeAttr('selected');
+              emptyOption.prop('selected', false); // IE9
+            }
             // Don't update the option when it is already selected.
             // For example, the browser will select the first option by default. In that case,
             // most properties are set automatically - except the `selected` attribute, which we