For new encryption types and for RC4, encrypt the krb_cred message in

For new encryption types and for RC4, encrypt the krb_cred message in
the initial gssapi token if credentials are being delegated.  For
consistency with Microsoft, we encrypt the credentials using the
session key not the subsession key.

Ticket: 1054

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@15091 dc483132-0cff-0310-8789-dd5450dbe970