IOSiPad ImagePickerView 拍照中，点击“use”，dismiss popover

iPad ImagePickerView 拍照中，点击“use”的同时，dismiss popover即消失所在的框，不必再点击其他区域。

UIImagePickerController的delegate如下：

#pragma mark - UIImagePickerController delegate methods

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingImage:(UIImage *)image editingInfo:(NSDictionary *)editingInfo
{
    if (image != nil) {
        [self.senderBtn setImage:image forState:UIControlStateNormal];
    }
    [picker dismissModalViewControllerAnimated:YES];
    [popoverController dismissPopoverAnimated:YES];//新增，可在点击“use”，使用并显示图片的同时，dismiss popoverController即消失拍照或取照框。
}

- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker
{
    [picker dismissModalViewControllerAnimated:YES];
}