fix(forms): fix SelectControlValueAccessor not to call onChange twice

Closes #5969

Author: vsavkin

modules/angular2/src/common/forms/directives/select_control_value_accessor.ts

@@ -36,11 +36,7 @@ export class NgSelectOption {
  */
 @Directive({
   selector: 'select[ngControl],select[ngFormControl],select[ngModel]',
-  host: {
-    '(change)': 'onChange($event.target.value)',
-    '(input)': 'onChange($event.target.value)',
-    '(blur)': 'onTouched()'
-  },
+  host: {'(input)': 'onChange($event.target.value)', '(blur)': 'onTouched()'},
   bindings: [SELECT_VALUE_ACCESSOR]
 })
 export class SelectControlValueAccessor implements ControlValueAccessor {

modules/angular2/test/common/forms/integration_spec.ts

@@ -348,7 +348,7 @@ export function main() {
              expect(sfOption.nativeElement.selected).toBe(true);
 
              select.nativeElement.value = 'NYC';
-             dispatchEvent(select.nativeElement, "change");
+             dispatchEvent(select.nativeElement, "input");
 
              expect(fixture.debugElement.componentInstance.form.value).toEqual({"city": 'NYC'});
              expect(sfOption.nativeElement.selected).toBe(false);