Unexpected FieldTypeEnum while parsing specific jpegs
Hi! While parsing this [JPEG](https://img.lemde.fr/2018/10/09/0/56/4770/3180/184/122/60/0/2616eb7_ZEmpnu_LH1c1xeTNOJ5uM5uh.jpg) with mitmproxy.

Traceback I got:
`File "mitmproxy/contentviews/__init__.py", line 130, in get_content_view ERROR 
  File "mitmproxy/contentviews/auto.py", line 17, in __call__	ERROR 
  File "mitmproxy/contentviews/image/view.py", line 36, in __call__	ERROR			
  File "mitmproxy/contentviews/image/image_parser.py", line 78, in parse_jpeg	ERROR			
  File "mitmproxy/contrib/kaitaistruct/exif_be.py", line 572, in ifd0	ERROR			
  File "mitmproxy/contrib/kaitaistruct/exif_be.py", line 31, in __init__	ERROR			
  File "mitmproxy/contrib/kaitaistruct/exif_be.py", line 522, in __init__	ERROR			
  File "enum.py", line 291, in __call__	ERROR			
  File "enum.py", line 533, in __new__	ERROR			
  File "enum.py", line 546, in _missing_	ERROR
ValueError: 9 is not a valid FieldTypeEnum	ERROR`

I think the main issue lies [here](https://github.com/kaitai-io/kaitai_struct_formats/blob/8ab8aa21bacfba94e900d7f05f2e902fef6e95ab/image/exif_be.ksy#L54). An unexpected FieldTypeEnum 9 is generated and throws error when `field_type` gets updated.

Would be glad to make changes to fix this.