Fix enum type generation
Fix enum type generation

Expressions like type(NicType.Nic) throwed an error, because special
attributes were not handled properly during class creation.

Change-Id: Ie9b7a8a0a20d7b9e356b5cb535484f5bf5b1eccb
Reviewed-by: Dave Reeve <6a84ee3ae0690d4584b99406fb3076392171f50e@morganstanley.com>

guillaume-philippon/aquilon,quattor/aquilon,quattor/aquilon,guillaume-philippon/aquilon,guillaume-philippon/aquilon,quattor/aquilon