Title: #822: tests: fix enctypes in test_copy_keytab
Currently test_copy_keytab uses legacy encryption types to mock up
keytab entries. New versions of libkrb5 might not support them anymore.
With this patch only supported encryption types should be used.
To pull the PR as Git branch:
git remote add ghsssd https://github.com/SSSD/sssd
git fetch ghsssd pull/822/head:pr822
git checkout pr822