selftest/knownfail.d: move encrypted_secrets to expectedfail.d

From the file itself:

> # The fl2000dc environment is provisioned with the --plaintext-secrets option
> # running the ecnrypted secrets tests on it and expecting them to fail.

Signed-off-by: Douglas Bagnall <douglas.bagnall@catalyst.net.nz>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

diff --git a/selftest/knownfail.d/encrypted_secrets b/selftest/expectedfail.d/encrypted_secrets
similarity index 100%
rename from selftest/knownfail.d/encrypted_secrets
rename to selftest/expectedfail.d/encrypted_secrets