SIRET : cleaning dashes and spaces added in prepare_value

Signed-off-by: CapsLock <faimaison@legeox.net>
Merge remote-tracking branch 'TheCapsLock/master'
Extended tests for ee1337411b6e1dfb834f2d424fa15bbe3abc6a1c.
Merge branch 'master' of github.com:django/django-localflavor