Remove des3 and arcfour from supported_enctypes

The des3 and arcfour (rc4) enctypes use weak string-to-key algorithms,
and should not be used for producing password-derived keys.

https://github.com/krb5/krb5/commit/38a31852c3e58f6e2f6b3b035a87f817d1db5537
Author: Tom Yu <tlyu@mit.edu>
Commit: 38a31852c3e58f6e2f6b3b035a87f817d1db5537
Branch: master
 src/include/osconf.hin |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)