Update Camellia feature description

Remove the potentially misleading "experimental" annotation on the
description of the Camellia encryption feature.

https://github.com/krb5/krb5/commit/7994997e058c631b11e04682d4d23e9b5a3c3613
Author: Tom Yu <tlyu@mit.edu>
Commit: 7994997e058c631b11e04682d4d23e9b5a3c3613
Branch: krb5-1.10
 doc/rst_source/mitK5features.rst |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)