tests: Add tests to check that OCB is only used for capable keys.
* tests/openpgp/samplekeys/ed25519-cv25519-sample-2.asc: New. * tests/openpgp/samplekeys/ed25519-cv25519-sample-1.asc: Add AEAD preference. * tests/openpgp/defs.scm (tr:gpgstatus): New. (create-legacy-gpghome): Also import .key private keys. * tests/openpgp/encrypt.scm: Add OCB tests.