Zero initialize ExifMnoteData<vendor> during construction with exif_mnote_data_<vendor>_new.

This is in order to not have an uninitialized 'mem' pointer in parent
ExifMnoteData after construction, when a non default ExifMem is used.

Bug: 205915333
Bug: 196085005

Test: create exif_mnote_data_<vendor>_new with non default exif mem using
      malloc debug; use exif_mem pointer from previously created
      ExifMnoteData, client app doesn't crash.

Change-Id: I35a393cdfb03755109aaa8f725b0792aef359dc6
Merged-In: Id106e79e829329145d27a93273241b58878bfac3
Signed-off-by: Jayant Chowdhary <jchowdhary@google.com>
4 files changed