Zero initialize ExifMnoteData<vendor> during construction with exif_mnote_data_<vendor>_new. am: c9da78d8d9 am: 31c126f5ac

Original change: https://googleplex-android-review.googlesource.com/c/platform/external/libexif/+/16248754

Change-Id: Ie03269d1b20bb70ba7c5fec489b9e8ade9de7e23